# Are there 39mp & 50mp+ Test Bodies in the Wild? [CR1]



## Canon Rumors Guy (Oct 22, 2012)

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<strong>More than 46.1 out there?


</strong>Northlight has received a couple of reports about larger megapixel EOS cameras out in the wild. The first one from the USA and sporting a 39mp sensor, and a second report from Asia about a camera well over 50mp. Both test cameras are in EOS-1 style bodies.</p>
<p>It’s stressed that neither camera is a production model and are strictly for testing.</p>
<p>I have no doubt the big megapixel DSLRs are in the pipeline, but so far things are pointing to the professional market instead of the consumer market.</p>
<p><strong>Source: [<a href="http://www.northlight-images.co.uk/cameras/Canon_1D_Xs.html" target="_blank">NL</a>]</strong></p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>
```


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## stewy (Oct 22, 2012)

I'd be more interested in the 39MP camera as opposed to the 50+ one. A 50+ MP photo would surely kill my 4 year old computer.


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## sanj (Oct 22, 2012)

Am happy that this is in the 1d style bodies. As I believe such hi mpx is for hi end use and pretty useless for general photographers.


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## Lee Jay (Oct 22, 2012)

sanj said:


> Am happy that this is in the 1d style bodies. As I believe such hi mpx is for hi end use and pretty useless for general photographers.



If it had easy-to-use crop and down-sample modes, it would be useful for consumers.

- 46.1MP full-res
- 11.5MP 3-color pixel mode (generated from 4 of the original pixels)
- 23MP 1.4x crop mode
- 18MP 1.6x-crop mode
- 11.5MP 2x-crop mode

Make these easily accessible while shooting by using a sliding switch around the shutter release like on the SX-series of hyperzooms and make them show in the viewfinder by use of a transmissive-LCD like on the 7D and you've got a great camera for consumers/enthusiasts.

By the way, I'm very unhappy they're 1D-style bodies, as I'd never own a body like that. I have very rare need for a portrait grip and don't want to carry one around all day when I don't need it. Further, the 1D bodies are too large for my hands. My 5D fits my hand like it was made for it.


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## Marsu42 (Oct 22, 2012)

stewy said:


> I'd be more interested in the 39MP camera as opposed to the 50+ one. A 50+ MP photo would surely kill my 4 year old computer.



No problem there - people spending $9k on a camera are likely to be able to afford a fast computer and enough storage space, too. And besides that, the eos cameras usually have a m-raw and s-raw mode, so s-raw from a 50mp cam might be 22mp just like on the 5d3 



sanj said:


> As I believe such hi mpx is for hi end use and pretty useless for general photographers.



But that's loop logic - just because amateurs don't use high mp now (because it's impossible) doesn't mean they won't use the added possibilities. Besides you could say or could have said the same about 12, 18 or 22mp.

Sure there is an absolute measure "print size", but mp is about cropping, too *esp.* in the hands of amateurs. And many amateurs do close-up or macro shots, too, so unless the sensor outresolves the Canon L zooms or macro lenses this is a common application.


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## RS2021 (Oct 22, 2012)

Lee Jay said:


> I'm very unhappy they're 1D-style bodies, as I'd never own a body like that. I have very rare need for a portrait grip and don't want to carry one around all day when I don't need it. Further, the 1D bodies are too large for my hands. My 5D fits my hand like it was made for it.



I wouldn't worry too much about that. Canon will have to release an "equivalent" to D800 at consumer prices (~$3600 to $4000?) in the short term, purely based on marketing needs. And they will. 

Agreed, Canon will try their best to "differentiate" these bodies... which means they will heavily cripple the high MP so there is still a market space for 5D-III. Some of it will be beyond their intervention like fps on such a high MP body. But expect a bigger bro to 5D III soon at a slightly higher price point.

Canon is only waiting for a "respectable" amount of time after the 5D-III release so the early 5D-III adoptors who paid full price $$$$$ don't jump off a cliff (if they hadn't already tried that after the Adorma or B&H "deals"...wink wink nod nod from Canon). 

This is similar to a greiving wife waiting a respectable amount of time before remarrying after her "dear" hubby dies.  

Canon will match D800 at a comparable "Canon" price soon (this is usually about ~$500 to $1000 more ?).


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## jrista (Oct 22, 2012)

A 50mp+ camera, especially if it does have improved DR and a 16bit ADC, sounds like a landscape and studio powerhouse! I'd never use such a camera for action photography, so I'd never need to import and wade through thousands of photos per shoot. I'd probably be able to use a single memory card for landscape outings. I already have a beefy computer, with SSD boot and data drives, so I'd not be too worried about PP editing performance. I hope they release something like that! It's what I've been waiting for as my next landscape camera.


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## K-amps (Oct 22, 2012)

Forget 50mp... just let me swap out my 5d3 sensor for something with NO AA filter... 

While Canon is at it... please play nice with Sony and Sigma and get us a 16DR with Foveon type non-bayerless 22mp sensor with 5d3 type high ISO performance. 


Wake up... what a wet dream that was...


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## jrista (Oct 22, 2012)

K-amps said:


> Forget 50mp... just let me swap out my 5d3 sensor for something with NO AA filter...
> 
> While Canon is at it... please play nice with Sony and Sigma and get us a 16DR with Foveon type non-bayerless 22mp sensor with 5d3 type high ISO performance.
> 
> ...



"Foveon type non-bayerless"??

And, wouldn't it be playing dirty and competitive, rather than nice and friendly (which they effectively are now) with Sony and Sigma if they integrated 16-bit ADC with a layered sensor?


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## RS2021 (Oct 22, 2012)

jrista said:


> A 50mp+ camera, especially if it does have improved DR and a 16bit ADC, sounds like a landscape and studio powerhouse! I'd never use such a camera for action photography, so I'd never need to import and wade through thousands of photos per shoot. I'd probably be able to use a single memory card for landscape outings. I already have a beefy computer, with SSD boot and data drives, so I'd not be too worried about PP editing performance. I hope they release something like that! It's what I've been waiting for as my next landscape camera.



The next target in all likelyhood would be the ~36MP range in a mid-level body to close the gap with Nikon's D800. Even if Canon can do the 50MP tmorrow, they will hold off and release incremental bodies to fleece the customers. This is not a critisism, it is just the way profitable companies work. My only complaint is I dont' get a cut .

Right now, there is no direct challange for Canon 35mm format at the 50MP level. But at 36MP there is! And at a cheaper price point. This is not sustainable in the long run. Canon will have to come up with a fair match.

On a more practical level, 50MP will have to be pricey, and someone willing to shell that kinda money will surelyl be looking at the bigboys in the Medium Format (MF). I dont' think Canon has any intention of wading into that pool anytime soon. But I do want to wish that your dreams eventually come true. I like the idea


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## sanj (Oct 22, 2012)

Marsu42 said:


> stewy said:
> 
> 
> > I'd be more interested in the 39MP camera as opposed to the 50+ one. A 50+ MP photo would surely kill my 4 year old computer.
> ...



I understand and see your cropping point. Pls explain term "loop logic", it sounds cool!


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## PerfectSavage (Oct 22, 2012)

<p>I have no doubt the big megapixel DSLRs are in the pipeline, but so far things are pointing to the professional market instead of the consumer market.</p>
<p><strong>Source: [<a href=\"http://www.northlight-images.co.uk/cameras/Canon_1D_Xs.html\" target=\"_blank\">NL</a>]</strong></p>
<p><strong><span style=\"color: #ff0000;\">c</span>r</strong></p>
[/html]
[/quote]

Of course, what would a consumer, or prosumer for that matter need 24+MP for? let alone 30 or 50? Prosumer camera MPs have gone down over the past few years, not up (G series, etc)...as have several pro bodies obviously other than 1Dx. It would be really interesting to see Canon introduce a professional studio camera though it would be difficult to unseat MF in that space, no? Are we looking at more of a 1Ds replacement/upgrade? 

My question, as I'm not an optics expert, is once you get into that realm of 30+ (if not before), how many current EF lenses are going to be able to leverage that sensor fully?


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## PerfectSavage (Oct 22, 2012)

Lee Jay said:


> sanj said:
> 
> 
> > Am happy that this is in the 1d style bodies. As I believe such hi mpx is for hi end use and pretty useless for general photographers.
> ...



Just curious, what would you require 46MP for?


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## stewy (Oct 22, 2012)

Marsu42 said:


> No problem there - people spending $9k on a camera are likely to be able to afford a fast computer and enough storage space, too. And besides that, the eos cameras usually have a m-raw and s-raw mode, so s-raw from a 50mp cam might be 22mp just like on the 5d3


Hehehe! I was wondering if anyone was going to comment on my statement. Yeah, my computer is nearing the end of its life for today's heavy graphics work. Its an overclocked quad core (3.0GHz) and I added a SSD earlier this year to boost performance. I'd surely build another one around the time I get a high MP camera. You do have a good point about the different modes. I never cared to use the smaller RAW formats since I'm currently capped at 10MP (40D). 

I'm curious to see what Canon has to show later this week.


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## Marsu42 (Oct 22, 2012)

stewy said:


> Yeah, my computer is nearing the end of its life for today's heavy graphics work.



It's just a matter of time (of which you won't have any if you're a pro), but for the rest of us a slower computer is still ok - when rendering focus stacks I'll queue them and let it render overnight on my dual-core 2ghz laptop :->



sanj said:


> Pls explain term "loop logic", it sounds cool!



:-> I looked up the real English term, it's "circular logic" - that's when the premise of a thesis is also the result.

An example is your thesis "amateurs don't need high mp cameras" - it cannot be disproven since there aren't any amateur high mp cameras (well, until the d800 that is, and that seems to sell), and the result of such a thesis (if adopted by Canon) is that there won't be any, apparently proving the thesis.


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## K-amps (Oct 22, 2012)

jrista said:


> "Foveon type non-bayerless"??
> 
> And, wouldn't it be playing dirty and competitive, rather than nice and friendly (which they effectively are now) with Sony and Sigma if they integrated 16-bit ADC with a layered sensor?



How the Folks far east; make love ; is no concern of mine


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## hiplnsdrftr (Oct 22, 2012)

Awesome... on a typical 4 day job I shoot 10,000 photos. So at 50mp each... it's a cluster f¥¢k.

I'll stick with 1Ds3 and 1Dx.


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## justsomedude (Oct 22, 2012)

> I have no doubt the big megapixel DSLRs are in the pipeline, but so far things are pointing to the professional market instead of the consumer market.



If it's true that the high MP Canons will launch in the $9k price range, I think it's safe to say we'll be entering the Nikon era for some many years to come.

The Canon ship seems to be lost at sea.


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## RS2021 (Oct 22, 2012)

hiplnsdrftr said:


> Awesome... on a typical 4 day job I shoot 10,000 photos. So at 50mp each... it's a cluster f¥¢k.
> 
> I'll stick with 1Ds3 and 1Dx.



+1 I am with ya!

Remember a time when on the audio side we had those Boomboxes with ever increasing Watts numbers plastered in big fonts on the speakers themselves? 10W, 20W, 45W, "100000000" W  While the mass market was being cluster f¥¢ked (to use your term), the audiophiles opted for Denon and other high-end brands with lower "apparent" specs but true "Hi-fidelity" and listening experience. This is why even today the Bose table top, simple as it is, costs more than a Sony audio receiver you can pick up at the department store.

1DX is worth every penny. I liken the the need for 50MP on a 35mm sensor to those who bought into the boomboxes with "100W" from each speaker. Mind you, I will buy it if the price is right cuz I can use one when I am doing yard work for easy listening . But if I am really in need for such high MP on my camera and committed to landscapes, and willing to pay a premium price, I'll be looking at Medium formats. 

Marketing wise, 50MP+ on a small 35mm format makes no sense at least for the near future. It comes down to the number of takers with that kinda money, whom we have to believe, will conveniently not consider medium format at that kinda money. Non starter.


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## jrista (Oct 22, 2012)

K-amps said:


> jrista said:
> 
> 
> > "Foveon type non-bayerless"??
> ...



You are one weird dude. ???


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## Lee Jay (Oct 22, 2012)

PerfectSavage said:


> Just curious, what would you require 46MP for?



Later cropping.

I've actually been asked to produce an 8x10 head-shot from a group photo after one of the people in the photo passed away later. That's some heavy cropping!


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## Mt Spokane Photography (Oct 22, 2012)

I shoot 500-1500 images at a time. I bought a D800, and after my first 500 image shoot, I was faced with days to process them, even with a fast pc and plenty of memory. A super pc might cut the time by 20%, but that would still not be something I'd want to face. The idea of buying a high mp camera only to use sraw seems silly to me. Eventually, computers may catchup, but for now, 50mp raw files would be for those who only take a few shots and want to spend a hour processing each one.


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## RS2021 (Oct 22, 2012)

Lee Jay said:


> PerfectSavage said:
> 
> 
> > Just curious, what would you require 46MP for?
> ...



I hope Canon is not betting on that small and that specific a market. Its like betting on finding that 5'10" supermodel with all her teeth from Alabama not related to her Cousin in other ways


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## Lee Jay (Oct 22, 2012)

Ray2021 said:


> Lee Jay said:
> 
> 
> > PerfectSavage said:
> ...



Oh, I've had that need a lot, and in lots of other ways as well. Some of it is engineering photography, where you can never have too much detail, and you aren't going to print any of the shots. Heck, I spent all last week shooting with a T2i and a 7D in situations where having this capability would have helped me a good bit.


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## sanj (Oct 22, 2012)

Marsu42 said:


> stewy said:
> 
> 
> > Yeah, my computer is nearing the end of its life for today's heavy graphics work.
> ...



Thank you!


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## TeenTog (Oct 22, 2012)

> a second report from Asia about a camera well over 50mp



Thats crazy! I was expecting a camera with a MP count in the 40s range. However if they did release a camera that high, the would also need to make something in the middle, such as a 39er. However, the 50MP camera would put canon at the top pf the non-medium format camera manufacturer... unless its a medium format camera!


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## LetTheRightLensIn (Oct 22, 2012)

sanj said:


> Am happy that this is in the 1d style bodies. As I believe such hi mpx is for hi end use and pretty useless for general photographers.



you believe wrong, even for reach alone, that is huge, give it 32-40MP density and crop modes so as to not waste file space, and you'd toss a lot more detail onto reach limited wildlife shots and not fill up HDs any faster, for starters


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## LetTheRightLensIn (Oct 22, 2012)

Lee Jay said:


> By the way, I'm very unhappy they're 1D-style bodies, as I'd never own a body like that. I have very rare need for a portrait grip and don't want to carry one around all day when I don't need it. Further, the 1D bodies are too large for my hands. My 5D fits my hand like it was made for it.



+1

although keep in mind that they did stress they were just pure test bodies and the rumor could be entirely fake too


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## hiplnsdrftr (Oct 22, 2012)

Obviously there are cases and assignments where 50mp would be beneficial...

the point is that they are rather specialized or few and far between.

For the shooters that need 50mp or think they need 50mp... go for it.


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## LetTheRightLensIn (Oct 22, 2012)

K-amps said:


> Forget 50mp... just let me swap out my 5d3 sensor for something with NO AA filter...
> 
> While Canon is at it... please play nice with Sony and Sigma and get us a 16DR with Foveon type non-bayerless 22mp sensor with 5d3 type high ISO performance.
> 
> ...



5D3 without AA filter would be pretty moire and aliased though no? it's only 20D photosite density


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## LetTheRightLensIn (Oct 22, 2012)

PerfectSavage said:


> My question, as I'm not an optics expert, is once you get into that realm of 30+ (if not before), how many current EF lenses are going to be able to leverage that sensor fully?



keep in mind that the latest Rebel is like 48MP FF equivalent


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## el bouv (Oct 22, 2012)

Counting pixels versus photosites could be confusing.
On an Foveon sensor you could count every pixel site a 3 effective pixels due to the stacked sensors.
So the mighty D800 with 36 MP could probably be a 12 MP Foveon sensor. Nikon has long had a use for 12 MP semsors.
In the same way Canon is stuck at 18 MP sensors so look out for a 54 MP Foveon type sensor from them.


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## K-amps (Oct 22, 2012)

el bouv said:


> Counting pixels versus photosites could be confusing.
> On an Foveon sensor you could count every pixel site a 3 effective pixels due to the stacked sensors.
> So the mighty D800 with 36 MP could probably be a 12 MP Foveon sensor. Nikon has long had a use for 12 MP semsors.
> In the same way Canon is stuck at 18 MP sensors so look out for a 54 MP Foveon type sensor from them.



It would seem that Bayer sensors have more spatial resolution than the stacked ones in Foveon (assuming you are X3'ing the foveon) .... I just like the rendition of the foveon colors has less artifacts and thus seems more pleasing... but in raw detail they are still a bit lacking than bayers...


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## dlleno (Oct 22, 2012)

LetTheRightLensIn said:


> PerfectSavage said:
> 
> 
> > My question, as I'm not an optics expert, is once you get into that realm of 30+ (if not before), how many current EF lenses are going to be able to leverage that sensor fully?
> ...



I don't have the answer either, but the pixel density of the all the latest 18mp crop bodies will probably eclipse some EF lenses, not to mention field techniques and less-than-optimum support. Jrista has pointed out that with optically the best (arguably) lens known to man (the 300mm f/2.8) and a tripod he can extract all of that resolving power. Someone with a deep knowledge of optical resolving power will have to chime in on this topic, but PerfectSavage you are raising a good point which needs a more precise answer.


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## K-amps (Oct 22, 2012)

LetTheRightLensIn said:


> K-amps said:
> 
> 
> > Forget 50mp... just let me swap out my 5d3 sensor for something with NO AA filter...
> ...



 True, if I was into shooting fabrics.


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## K-amps (Oct 22, 2012)

jrista said:


> K-amps said:
> 
> 
> > jrista said:
> ...



Saving this Quote:

The next time you go accusing others of making personal attacks.


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## dlleno (Oct 22, 2012)

for additional techical discussion on the topic of line pairs per mm and sensor resolving power, see this thread

http://www.canonrumors.com/forum/index.php?topic=3393.0

in which *Jrista * reports that for the 116 lp/mm resolving power of the 18mp sensor itself, "The extremely high resolution of the 7D also means that outside of the best of the most recent Canon L-series lenses, namely Mark II's and new designs like the 8-15mm L Fisheye, the 7D is very likely outresolving most lenses except for their very centers" Sorry Jrista I yanked that out of the above thread without quoting properly. 

so -- to me this means if you show Jrista a lens with less than 116 lp/mm resolving power in the center, at apertures that are abberation limited**, then he will show you a lens that is not capable of taking advantage of the 18mp sensor resolving power. 

** means a limitation of the glass itself, i.e. not due to small apertures which introduce diffraction and futher loss of resolving power.


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## jrista (Oct 22, 2012)

K-amps said:


> jrista said:
> 
> 
> > K-amps said:
> ...



Oh, I wasn't verbally mauling you or anything like that (I've been on the receiving end of that numerous times recently.) I was just making an observation, as I couldn't make heads or tails of your previous two posts.  

Besides, weird ain't bad, its just weird. I'm ultra weird myself. ???


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## K-amps (Oct 22, 2012)

jrista said:


> K-amps said:
> 
> 
> > jrista said:
> ...



It's cool, I was just having some fun myself. 

When you said "Playing Dirty....." my mind wandered over to the Adult Anime section of the VHS rentals.... hence the quip I made. about love making in the east... now why I would expect anyone to make "that " connection


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## jrista (Oct 22, 2012)

K-amps said:


> jrista said:
> 
> 
> > K-amps said:
> ...



Bad images....baaad images......


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## Lee Jay (Oct 22, 2012)

dlleno said:


> for additional techical discussion on the topic of line pairs per mm and sensor resolving power, see this thread
> 
> http://www.canonrumors.com/forum/index.php?topic=3393.0
> 
> in which *Jrista * reports that for the 116 lp/mm resolving power of the 18mp sensor itself, "The extremely high resolution of the 7D also means that outside of the best of the most recent Canon L-series lenses, namely Mark II's and new designs like the 8-15mm L Fisheye, the 7D is very likely outresolving most lenses except for their very centers" Sorry Jrista I yanked that out of the above thread without quoting properly.



It's baloney, though. I use TCs on lenses on those 18MP 1.6-crop sensors, and the TCs greatly enhance detail retained compared to the bare lens. I've used 1.4x and 2x stacked on a T2i with a 70-200/2.8L IS II - that's the equivalent of a (18MP)*(1.6^2)*(2^2)*(1.4^2) = 369MP full-frame camera shooting through the bare lens. Even a 100-400L will retain more detail using a 2x versus a 1.4x on that sensor. That's like a 184MP full-frame sensor.

Secondly, adding pixels will always retain more detail through the same optics than having fewer. The function is asymptotic. There's no "the sensor is out-resolving and so there's no point" type limit beyond which you can't cross.


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## jrista (Oct 22, 2012)

Lee Jay said:


> dlleno said:
> 
> 
> > for additional techical discussion on the topic of line pairs per mm and sensor resolving power, see this thread
> ...



You still have a very skewed idea, or simply bad terminology, in describing what you are actually experiencing with a TC, though, Lee Jay. Your previous argument in that other thread, that the virtual image of the sensor shrinks when it is observed by looking through the lens into the camera is not indicative of what is really occurring. A teleconverter does not change how many megapixels you have, nor does it change the resolution of the lens. The physical spatial resolution of the sensor is fixed. You are simply magnifying your subject more, and projecting a smaller area of your subject at a larger magnification on the sensor. 

As we discussed in our last debate, the spatial resolution of whatever is projected by the lens, as well as the spatial resolution of the sensor, are pretty limited. If you use a TC or multiple TC's that reduce your aperture to f/8, then according to the laws of physics spatial resolution becomes limited (specifically to around 86lp/mm), which is WELL below the fixed luminance spatial resolution of pretty much any APS-C sensor these days. Spatial resolution is not increasing, *magnification* is increasing. Disjoint concepts that can work together to produce a more detailed image without actually changing spatial resolution of the real image at the sensor. 

I think what you are doing is accounting for the "entire" size of your subject. If you magnify a part of the moon such that only that one part fits on an 18mp sensor, the "effective size of the whole moon if it were to be measured in megapixels would require a 184mp FF sensor to image in it's entirety." You could look at it that way, but it is extremely confusing, and running about stating "It's like having a 369MP FF sensor" is not really true, and I WILL argue that point whenever you bring it up. ;P In short: 

Magnification != Increase in Spatial Resolution

Explicitly:

Magnification == Increase in Subject Size with Same Spatial Resolution

The equating of magnification with an increase in spatial resolution is a misnomer. Technically speaking, you can *either* increase subject size by optically magnifying it to record more detail of a smaller area of your subject, OR you could increase the spatial resolution of your recording device (image sensor) to gather more detail of the SAME area, which would concurrently have the effect of allowing you to crop a smaller area with the same amount of detail as if you had optically magnified. The two achieve similar results, but they are not the same thing, and magnification should not be equated directly to an increase in sensor spatial resolution.


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## Lee Jay (Oct 22, 2012)

jrista said:


> You still have a very skewed idea, or simply bad terminology, in describing what you are actually experiencing with a TC, though, Lee Jay. Your previous argument in that other thread, that the virtual image of the sensor shrinks when it is observed by looking through the lens into the camera is not indicative of what is really occurring. A teleconverter does not change how many megapixels you have, nor does it change the resolution of the lens.



No, but it has the same effect as doing either one.

As we discussed in our last debate, the spatial resolution of whatever is projected by the lens, as well as the spatial resolution of the sensor, are pretty limited. If you use a TC or multiple TC's that reduce your aperture to f/8, then according to the laws of physics spatial resolution becomes limited (specifically to around 86lp/mm), which is WELL below the fixed luminance spatial resolution of pretty much any APS-C sensor these days.[/quote]

f=1/lambda*f#

http://en.wikipedia.org/wiki/Spatial_cutoff_frequency

f=1/(0.00055*8) = 227lp/mm at MTF = 0. Using MTF=50, as you did above, is arbitrary and of little value in this context.



> Spatial resolution is not increasing, *magnification* is increasing.



Same thing, since the optics (the lens) didn't change.



> I think what you are doing is accounting for the "entire" size of your subject. If you magnify a part of the moon such that only that one part fits on an 18mp sensor, the "effective size of the whole moon if it were to be measured in megapixels would require a 184mp FF sensor to image in it's entirety." You could look at it that way, but it is extremely confusing, and running about stating "It's like having a 369MP FF sensor" is not really true, and I WILL argue that point whenever you bring it up.



That's fine, and you'll be wrong each time. This is the way people do it in astrophotography, where resolution is what you are after. "Image scale" is determined by arc-second per pixel, and the lens is measured by aperture diameter. TCs leave the aperture unchanged and decrease arc-seconds per pixel. More pixels leave the aperture unchanged and decrease arc-seconds per pixel. Same thing.


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## jrista (Oct 22, 2012)

Lee Jay said:


> jrista said:
> 
> 
> > You still have a very skewed idea, or simply bad terminology, in describing what you are actually experiencing with a TC, though, Lee Jay. Your previous argument in that other thread, that the virtual image of the sensor shrinks when it is observed by looking through the lens into the camera is not indicative of what is really occurring. A teleconverter does not change how many megapixels you have, nor does it change the resolution of the lens.
> ...



The effects are different. If you have an 18mp sensor and a 36mp sensor, and use the same lens on both. The effect of switching from the 18mp sensor to the 36mp sensor has the effect of potentially doubling spatial resolution for the entire area of the object being photographed. (Let's assume for a moment that you have a perfect lens at a very wide aperture, so diffraction is not a problem.) On the other hand, adding a 2x teleconverter has the effect of enlarging the subject, such that a smaller area of that subject is being photographed at the same spatial resolution.

In the first case, you increase the resolution of a much larger subject equally. As such, a sensor with a higher resolution is a hell of a lot better than a teleconverter, since the teleconverter is cropping, for all intents and purposes. It is enforcing that a certain amount of your subject will fall outside of the bounds of the sensor, since it has been enlarged. 

Using a teleconverter changes what your resolving by reducing field of view, where as changing the sensor increases your resolving power for the same field of view. A teleconverter can make a smaller FOV better, but a higher resolution can make the same FOV better. Definitely not the same thing, and it is misleading to assume or discuss them as if they are the same thing. 



Lee Jay said:


> > As we discussed in our last debate, the spatial resolution of whatever is projected by the lens, as well as the spatial resolution of the sensor, are pretty limited. If you use a TC or multiple TC's that reduce your aperture to f/8, then according to the laws of physics spatial resolution becomes limited (specifically to around 86lp/mm), which is WELL below the fixed luminance spatial resolution of pretty much any APS-C sensor these days.
> 
> 
> 
> ...



The notion that a consumer-grade camera can resolve anything at MTF ZERO is ludicrous. The notion that a camera can usefully resolve anything at MTF 9% (Reighley) is also pretty ridiculous. MTF 50% is of specific value because MTF 50% IS STILL and WILL CONTINUE to be used today as the standard benchmark for image resolution of meaningful sharpness, either by a lens or a sensor. Low MTF image analysis, such as at just above (but not actually at) MTF 0% is used by specialized software to analyze patterns of point light sources (stars) against a black background, in an effort to try and determine if the stars are binary or tertiary. MTF 0% photography is only used in extreme scientific scenarios, it has never held any value in real-world photography. There is little data to indicate that a modern image sensor, even one with microlenses, can really produce any kind of useful output at MTF 9% due to Poisson distribution of photons (photon shot noise)...you could never really know whether two adjacent pixels were different because of meaningful image detail, or simply because of noise.

So I'm sorry, but I beg to differ. MTF 50% is the only valid level of contrast to meaningfully and consistently discuss spatial resolution in the context of consumer-grade lenses and sensors. 



Lee Jay said:


> > Spatial resolution is not increasing, *magnification* is increasing.
> 
> 
> 
> Same thing, since the optics (the lens) didn't change.



That is 100% factually incorrect. The optics DID change...you added a teleconverter. A teleconverter is optics. (Are you sure you are not confusing extension tubes for a teleconverter? If you add extension tubes, then the optics themselves do not change, but they DO move farther from the sensor, which might require a change in focus, which in turn does change the optical configuration and potentially magnification.)



Lee Jay said:


> > I think what you are doing is accounting for the "entire" size of your subject. If you magnify a part of the moon such that only that one part fits on an 18mp sensor, the "effective size of the whole moon if it were to be measured in megapixels would require a 184mp FF sensor to image in it's entirety." You could look at it that way, but it is extremely confusing, and running about stating "It's like having a 369MP FF sensor" is not really true, and I WILL argue that point whenever you bring it up.
> 
> 
> 
> That's fine, and you'll be wrong each time. This is the way people do it in astrophotography, where resolution is what you are after. "Image scale" is determined by arc-second per pixel, and the lens is measured by aperture diameter. TCs leave the aperture unchanged and decrease arc-seconds per pixel. More pixels leave the aperture unchanged and decrease arc-seconds per pixel. Same thing.



The arc seconds per pixel remain the same, but the result is not the same. In one case, arc seconds per pixel decrease for the same number of pixels. In the other case, arc seconds per pixel decrease for MORE PIXELS. They are definitely different things. The only case where they would be the same is if you always and explicitly included the notion that you were CROPPING the larger sensor's image to the same area and dimensions of the smaller sensor. In which case, and only in which case, would the results be exactly the same thing. 

In every case, using an better sensor that actually has more resolution will always be better than using a teleconverter, because you can resolve more detail of the same subject. Using a teleconverter on the same lower resolution sensor, you are changing your subject. It doesn't matter if the arc seconds per pixel are the same, the resulting output image from the two systems is very different.


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## dlleno (Oct 22, 2012)

nicely articulated Jrista. a clarification pls on a related topic:



jrista said:


> ... A teleconverter does not change ... the resolution of the lens.



but it can change the optical resolution of the optical system 


> ...If you use a TC or multiple TC's that reduce your aperture to f/8, then according to the laws of physics spatial resolution becomes limited (specifically to around 86lp/mm)



You're refering to diffraction artifacts here, but for example a bad 1.4TC on an f/2.8 lens introduces new optical elements and hence the potential for a reduction in resolution of the optical system, still avoiding any diffraction related side effects caused by a narrow aperture. 

As for the question posed by PerfectSage, there does appear to be a real and practical answer, or at least rule of thumb, which would guide one towards the goal of advantaging all of that 116 lp/mm resolving power of the 7D sensor, and that is to choose optics that will present an image to the sensor with enough inherent detail. if the source image truly does not contain the detail, the sensor will not find any that isn't there. Whether or not that goal is a good one or not can be debated of course


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## RS2021 (Oct 22, 2012)

As always we have descended into "I-need-120MP-on-a tiny area-cuz-I-can-argue-it-will-work".

Prior to the 1DX and 5D-III release, the same crowd (you know who you are, you have spent hours typing pages on here selling the same old 3 day old fish) screamed for 40+ MP and were bitterly disappointed when Canon went the low MP route for both bodies. 

Its not about what you "want"...its about what they can sell in a profitable way in a competitive market. 
Most pros own a 1DX... not 7D... so much for the high MP whining. Every flagship that Nikon and Canon have released so far have been lower MP while they release high MP APC and consumer grade bodies for the "My-MP-is-Bigger-than-your-MP" crowd. 

I guess learning comes a tad slow... but there is no harm in asking....please continue


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## jrista (Oct 22, 2012)

dlleno said:


> nicely articulated Jrista. a clarification pls on a related topic:
> 
> 
> 
> ...



I wouldn't disagree with that. Optical resolution specifically refers to a "systems" ability to resolve detail of "some subject". If, by magnifying the subject, the system can resolve _part_ of the subject in more detail, then yes, optical resolution increased. That is, effectively, magnification. However, the spatial resolution of the system does not necessarily change, and it is spatial resolution we are discussing. 

Technically speaking, if you can increase focal length while maintaining or increasing aperture, then spatial resolution could concurrently increase along with optical resolution (magnification). But the process of adding a TC precludes that option, since focal length increases but entrance pupil remains the same, therefor necessitating a smaller relative aperture, which in turn dictates a lower spatial resolution for the lens (which is only one component of the system...sensor spatial resolution remains the same, thus...sensor outresolves lens.) 



dlleno said:


> > ...If you use a TC or multiple TC's that reduce your aperture to f/8, then according to the laws of physics spatial resolution becomes limited (specifically to around 86lp/mm)
> 
> 
> 
> You're refering to diffraction artifacts here, but for example a bad 1.4TC on an f/2.8 lens introduces new optical elements and hence the potential for a reduction in resolution of the optical system, still avoiding any diffraction related side effects caused by a narrow aperture.



The additional optics have the potential to introduce new optical aberrations, which themselves have the potential to reduce spatial resolution. Assuming the optics of a bad TC introduce enough optical aberrations to overpower the effects of diffraction...well, that only means that you have even LESS resolution than if you were working with a diffraction-limited lens, *not more*. Optical aberrations have the potential to be far more devastating to IQ than diffraction, so even with an f/2.8 lens, if you are using a crappy 1.4x TC with the lens wide open, I'd expect the results to be worse than if you used a good TC on an f/4 lens. 



dlleno said:


> As for the question posed by PerfectSage, there does appear to be a real and practical answer, or at least rule of thumb, which would guide one towards the goal of advantaging all of that 116 lp/mm resolving power of the 7D sensor, and that is to choose optics that will present an image to the sensor with enough inherent detail. if the source image truly does not contain the detail, the sensor will not find any that isn't there. Whether or not that goal is a good one or not can be debated of course



Technically speaking, there is an asymptotic relationship in terms of spatial resolution. You can never actually achieve the same spatial resolution as the highest resolving component in an optical system. As you approach it, you begin to experience diminishing returns. Lets say you have a lens capable of resolving 86lp/mm. Nothing you ever do can ever allow you to resolve 86.1lp/mm...your upper bound is the resolution of the lens itself. At best, you could reach 85.99999999999... lp/mm, assuming you had a sensor with literally infinite resolution. You would need something like an f/0.3 lens to resolve around 115lp/mm of resolution, and approach the 116lp/mm of the 7D. Total "system spatial resolution" is derived from the RMS of the "blur circle" of each component in an optical system. The size of the airy disc at a given aperture in the lens, blur introduced by any and all TC's, the size of a pixel in the sensor, and if you want to get really accurate, the size of the blur introduced by low-pass and IR cut filters. Taking the RMS of each of those will give the the size of the blurry disc of a single point light source resolved by the entire system. Taking the reciprocal of that divided by two will give you the spatial resolution of the system as a whole in lp/mm.

With a good lens and the 7D, the actual system spatial resolution is only going to be around 70-90lp/mm at best, and probably closer to 50lp/mm on average (accounting for varying apertures and varying lenses of varying quality.)


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## jrista (Oct 22, 2012)

Mikael Risedal said:


> Lee Jay said:
> 
> 
> > dlleno said:
> ...



Again, you are missing the point of debate. I'm not talking about simply getting more resolution by using a better lens. I'm debating the notion that adding a TC is the same exact thing as using a higher resolution sensor, or that the two can be discussed in terms of megapixels.


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## wickidwombat (Oct 22, 2012)

sanj said:


> Am happy that this is in the 1d style bodies. As I believe such hi mpx is for hi end use and pretty useless for general photographers.


what elitest hogwash! : -100 for such an arrogant and ill concieved post
I for one dont want an overbulky 1D style body as many others do not want them either
there is no reason or need for them these days. infact the Smaller 5D style body is better for a high MP audience since its more compact and lighter its less bulk and weight to carry around hiking to get to that magic landscape shooting location to take advantage of the billions of pixels.
and in the studio with that many megapixels its going to be shot like a medium format. On a tripod and tethered capturing the whole area then cropping later as desired.


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## RS2021 (Oct 22, 2012)

Mikael Risedal said:


> both Canon and Nikon could put up with a sensor with higher resolution,but what would they gain from it ?



My argument was not to support the insane MP requests by a vocal group of enthusiasts...the post was to say pros and Canon know MP evolves in the context of sensor size and demands of what the pro market's quality needs are (including DR, fps, ISO performance) are. Both Nikon and Canon have shown by their choice of low MP for pro bodies what faction drives their innovation on flagships. It’s NOT high MP. 

They do release "enthusiast" bodies with pumped up MP... but apparently they aren't moving quickly enough to cram more MP in that tiny wafer of a APC sensor for the high MP Crowd 

My point is Canon will move at its own pace, not based on the vocal few who think more is always better.


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## LetTheRightLensIn (Oct 22, 2012)

K-amps said:


> LetTheRightLensIn said:
> 
> 
> > K-amps said:
> ...



what about ripples on a lake or fallen leaves on a forest floor or jagged rocks, etc.


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## Lee Jay (Oct 22, 2012)

jrista said:


> Lee Jay said:
> 
> 
> > jrista said:
> ...



They are the same. Smaller pixels and longer focal length, both given the same aperture diameter, do the same thing. See for yourself:

http://photos.imageevent.com/sipphoto/samplepictures/Pixel%20density%20versus%20teleconverters.jpg



> If you have an 18mp sensor and a 36mp sensor, and use the same lens on both. The effect of switching from the 18mp sensor to the 36mp sensor has the effect of potentially doubling spatial resolution for the entire area of the object being photographed. (Let's assume for a moment that you have a perfect lens at a very wide aperture, so diffraction is not a problem.) On the other hand, adding a 2x teleconverter has the effect of enlarging the subject, such that a smaller area of that subject is being photographed at the same spatial resolution.



That's a separate issue (FOV/vignetting) having nothing to do with resolving power.



Lee Jay said:


> > As we discussed in our last debate, the spatial resolution of whatever is projected by the lens, as well as the spatial resolution of the sensor, are pretty limited. If you use a TC or multiple TC's that reduce your aperture to f/8, then according to the laws of physics spatial resolution becomes limited (specifically to around 86lp/mm), which is WELL below the fixed luminance spatial resolution of pretty much any APS-C sensor these days.
> 
> 
> 
> ...


Yeah...that's the definition of MTF 0. It's the asymptote.



> The notion that a camera can usefully resolve anything at MTF 9% (Reighley) is also pretty ridiculous.



Except that we do so all the time, in astro stuff.



> MTF 50% is of specific value because MTF 50% IS STILL and WILL CONTINUE to be used today as the standard benchmark for image resolution of meaningful sharpness, either by a lens or a sensor.



Meaningful image sharpness is meaningless term. People that espouse this ridiculous property also claim that reducing pixel count gets you are sharper image, which is impossible.



Lee Jay said:


> > Spatial resolution is not increasing, *magnification* is increasing.
> 
> 
> 
> Same thing, since the optics (the lens) didn't change.



That is 100% factually incorrect. The optics DID change...you added a teleconverter.[/quote]

I added it behind the lens. It doesn't change the performance of the lens at all.



Lee Jay said:


> > I think what you are doing is accounting for the "entire" size of your subject. If you magnify a part of the moon such that only that one part fits on an 18mp sensor, the "effective size of the whole moon if it were to be measured in megapixels would require a 184mp FF sensor to image in it's entirety." You could look at it that way, but it is extremely confusing, and running about stating "It's like having a 369MP FF sensor" is not really true, and I WILL argue that point whenever you bring it up.
> 
> 
> 
> That's fine, and you'll be wrong each time. This is the way people do it in astrophotography, where resolution is what you are after. "Image scale" is determined by arc-second per pixel, and the lens is measured by aperture diameter. TCs leave the aperture unchanged and decrease arc-seconds per pixel. More pixels leave the aperture unchanged and decrease arc-seconds per pixel. Same thing.



The arc seconds per pixel remain the same, but the result is not the same.[/quote]

As I demonstrated above with actual samples, it is.



> In one case, arc seconds per pixel decrease for the same number of pixels. In the other case, arc seconds per pixel decrease for MORE PIXELS. They are definitely different things.



Only because of FOV, which is another topic than resolving power.



> The only case where they would be the same is if you always and explicitly included the notion that you were CROPPING the larger sensor's image to the same area and dimensions of the smaller sensor. In which case, and only in which case, would the results be exactly the same thing.



Good, I'm glad you finally agree with me. Seems we're done here.



> In every case, using an better sensor that actually has more resolution will always be better than using a teleconverter, because you can resolve more detail of the same subject.



And because the smaller pixels don't have the optical aberrations of a teleconverter. However, given that I can't do anything to my camera to reduce it's pixel size, adding a teleconverter is the closest thing to simulate the same effect, albeit with a slightly lower performance due to aberrations.

You're also missing a crucial bit of this.

Let's say your lens is capable of 100lp/mm at MTF 50. If your sensor already resolves 100lp/mm, you constantly imply that there's not much point in going to smaller pixels. That is utterly and totally false.


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## jrista (Oct 22, 2012)

Ray2021 said:


> My point is Canon will move at its own pace, not based on the vocal few who think more is always better.



And more power too them, too! I'd rather have a well thought out high MP camera that offered users useful features, than something that turned out to be far too difficult to use, or produced images of such an immense size as to be unusable for most photographers.


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## RS2021 (Oct 22, 2012)

Question from a 18MP user who rarely feels the need for more. How many Megapixels is enough for the high MP hogs in the 35mm sensor format? Lets take two L lenses specifically... EF 24mm f1.4 L MII and 70-200 2.8L MII. (what you will use it for, is a totally different question, but lets keep it simple).


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## expatinasia (Oct 22, 2012)

I find it funny that people are saying pros would not want this. Anyone that has been in a working media centre at a major international sporting event knows just how much cropping often goes into the pics they use.

Plus, computers these days - even laptops - can handle such large sizes. And if you are spending US$6-10,000 on a body you most likely can afford to get a decent laptop in the config needed for such file sizes. Remember, you may take thousands of pictures at an event, but you do not use them all!!

I would welcome such a camera in a 1 body. Main thing that would interest me is how far they can push the fps in such a monster. If it is just 4-5 I would not be interested but if they can push it to 6-8 or even more ;-) then ok.


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## RS2021 (Oct 22, 2012)

Mikael Risedal said:


> you have already got the answers, what the camera is aiming at=sports, se above



I beg to differ...sports is one of the uses for a camera like 1DX... not the only one.


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## jrista (Oct 23, 2012)

Lee Jay said:


> jrista said:
> 
> 
> > Lee Jay said:
> ...



You are only thinking pixel size, which I guess is one way to look at it. The OUTPUT of the two systems is entirely different, though. In the case of a denser sensor, you get a more detailed image of a LARGER area of your subject. In the case of a less dense sensor combined with a TC, you get a more detailed image of a SMALLER area of your subject. The two are not the same, even if in an abstract context the arc seconds per pixel is equivalent. In terms of the actual product of the two systems, the higher density sensor is always the better system. Additionally, adding a TC does not increase "spatial" resolution, it increases "system" resolution, which is a different concept.



Lee Jay said:


> > If you have an 18mp sensor and a 36mp sensor, and use the same lens on both. The effect of switching from the 18mp sensor to the 36mp sensor has the effect of potentially doubling spatial resolution for the entire area of the object being photographed. (Let's assume for a moment that you have a perfect lens at a very wide aperture, so diffraction is not a problem.) On the other hand, adding a 2x teleconverter has the effect of enlarging the subject, such that a smaller area of that subject is being photographed at the same spatial resolution.
> 
> 
> 
> That's a separate issue (FOV/vignetting) having nothing to do with resolving power.



If you are referring to optical system resolution, rather than spatial resolution, then I agree. However you keep applying the units "lp/mm" to system resolution, which feels like a major conflation to me. Assuming the optical spatial resolution of the entire lens setup (original lens + TC) remains the same (which is generally impossible when adding a TC, as it reduces your REALTIVE aperture, which implicitly means your optical spatial resolution of THE ENTIRE LENS SETUP is reduced), the final system _spatial_ resolution will be lower than that of the lens or the sensor, as it is the root mean square of the blur each individual component.



Lee Jay said:


> Lee Jay said:
> 
> 
> > > As we discussed in our last debate, the spatial resolution of whatever is projected by the lens, as well as the spatial resolution of the sensor, are pretty limited. If you use a TC or multiple TC's that reduce your aperture to f/8, then according to the laws of physics spatial resolution becomes limited (specifically to around 86lp/mm), which is WELL below the fixed luminance spatial resolution of pretty much any APS-C sensor these days.
> ...



Yes, it is the asymptote. It is also a purely theoretical construct. I read an interesting quote today: 



various]In theory there is no difference between theory and practice. In practice there is.[/quote]
You have to take into account the realities that exist in practice that don't exist in pure theory. In reality said:


> > The notion that a camera can usefully resolve anything at MTF 9% (Reighley) is also pretty ridiculous.
> 
> 
> 
> Except that we do so all the time, in astro stuff.



You need to back that up with some actual examples that are properly analyzed for MTF. MTF 0% means 0% contrast. At that point, you are literally analyzing the specific shape of the spot resolved for a point light source like a star to make EDUCATED GUESSES about the nature of a star. Is that star a single star? Is it a binary star? Might it be a tertiary star system? Those analyses are also performed algorithmically by computers, and the stars need to be isolated against a dark backdrop, so the shape and waveform of the airy disc that was resolved is as clear and separate from background noise as possible. It has no application in general "photography", where we are resolving a system of point light sources to create a continuous signal. Even in the case of hobbyist astrophotography, you are not resolving point light sources for a _scientific purpose_...you are resolving stars (plural), nebula, galazies, nova, etc. to produce a photograph for *aesthetic purposes*.

Different contexts. And, therefor, different *STANDARD* systems by which we measure spatial resolution. I use MTF 50% because it is the industry standard MTF that major products, like Imatest, use. 



Lee Jay said:


> > MTF 50% is of specific value because MTF 50% IS STILL and WILL CONTINUE to be used today as the standard benchmark for image resolution of meaningful sharpness, either by a lens or a sensor.
> 
> 
> 
> Meaningful image sharpness is meaningless term. People that espouse this ridiculous property also claim that reducing pixel count gets you are sharper image, which is impossible.



If no one ever complained about the sharpness of properly stabilized photos taken with a camera like the 7D, then I would agree with you. Simple fact of the matter is that once your sensor spatial resolution starts to outresolve your subject, details DO appear less-sharp than if the same photo, with the same lens, was taken with a sensor with larger pixels. It is an AESTHETIC, real-world thing. Not a theoretical thing. It is a matter of perception, not statistical measurement. Statistically, no matter how you slice and dice it, the 7D resolves more, and has the capability to resolve more detail as sharply as a sensor with larger pixels. Perceptually, the 7D tends to produce soft results in a non-normalized context (i.e. pixel peeping) than sensors with larger pixels. 

Context, man. You have to discuss (and understand) things in context. 



Lee Jay said:


> Lee Jay said:
> 
> 
> > Lee Jay said:
> ...



Ok, now you are mincing words. Lets be specific and accurate here. The sensor, that tiny, wonderous little device setting inside the mirror box of your camera...that is what is actually resolving the image projected by your "lens setup". It doesn't care if the "original lens" remained unchanged. It cares about the entire "lens setup", which includes not only the "original lens", but also a "teleconverter". The entire "lens setup" is what matters in the context of the discussion at hand....the SPATIAL resolution of sensors, lens setups, and the optical system as a whole.

In the context of the SENSOR, if you add a TELECONVERTER to a LENS, the optics ABSOLUTELY DO CHANGE. The sensor doesn't sit between the lens and the TC...the sensor sits behind BOTH the lens and the TC. Lets stop playing games now.


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## jrista (Oct 23, 2012)

Lee Jay said:


> > In one case, arc seconds per pixel decrease for the same number of pixels. In the other case, arc seconds per pixel decrease for MORE PIXELS. They are definitely different things.
> 
> 
> 
> Only because of FOV, which is another topic than resolving power.



Optical resolving power. It matters in the context of the discussion on spatial resolution, which is what we are talking about. 



Lee Jay said:


> > The only case where they would be the same is if you always and explicitly included the notion that you were CROPPING the larger sensor's image to the same area and dimensions of the smaller sensor. In which case, and only in which case, would the results be exactly the same thing.
> 
> 
> 
> Good, I'm glad you finally agree with me. Seems we're done here.



Cheap. Real cheap. 



Lee Jay said:


> > In every case, using an better sensor that actually has more resolution will always be better than using a teleconverter, because you can resolve more detail of the same subject.
> 
> 
> 
> ...



I'm not missing anything. You seem to still be missing my point. Using a teleconverter will produce the same arc seconds per pixel, but for a smaller area of the subject. My debate with you is the way you directly equate the use of a TC with the use of a higher resolution sensor. The two are not equivalent, not by orders of magnitude. One may "simulate" the other, however it is quite plain and simply not "as good" as the alternative. You lose something with a TC that you do not lose with a higher resolution sensor. Claiming that a TC is "the exact same thing" based solely on the notion that arc seconds per pixel is the same is factually incorrect, and highly misleading. 



Lee Jay said:


> Let's say your lens is capable of 100lp/mm at MTF 50. If your sensor already resolves 100lp/mm, you constantly imply that there's not much point in going to smaller pixels. That is utterly and totally false.



No, I don't imply that there is no point in going to smaller pixels. I believe I even did the math on this the last time we had this debate. My only argument is that you begin to experience diminishing returns by going to smaller pixels, and then within the context of lenses below a certain aperture (I believe I used f/4 as a rough market for the cutoff point, below which you definitely get diminishing returns as sensor resolution increases.)

For discussions sake, let's take your 100lp/mm lens, and 100lp/mm sensor. In terms of individual blur, both exhibit a 5 micron blur circle. The system blur would be:


```
sqrt(0.005^2 + 0.005^2)
```

That comes out to a system blur of 0.007um, or in terms of lp/mm, about 70lp/mm. Now, lets say we double the sensor's resolution. We now have a sensor capable of 200lp/mm. Our system blur changes, but not by the same ratio. Its 0.0056um, or about 89lp/mm. Lets say we switch to a 400lp/mm sensor. We are up to 97lp/mm. We still haven't reached 100lp/mm, but our sensor is now a 552mp sensor, with 1.25um pixels! Diminishing returns. Even at a mere 200lp/mm, our sensor is 138mp with 2.5um pixels.

My argument before was that it is a highly costly endeavor to improve system resolution by increasing sensor resolution. Especially given the fact that by the time we reach around f/3.5, diffraction (in a literal perfect lens) is limiting the maximum spatial resolution of whatever optical setup we are using to below 200lp/mm MTF 50 anyway, so using a 500mp sensor is rather meaningless outside of the context of optically perfect (diffraction limited) ultra fast lenses. Even a $2500 50mm f/1.2 lens exhibits some optical aberrations as narrow as f/3.5-f/4.

Oh, and BTW...astrophotography, assuming that, with a subject such as the moon, you could resolve details of lower contrast than 50% and not end up having to pose the question "Is that detail noise, or is it the moon?", that is a rather specialized case for a small niche of photographers. In the broader context of "all photography", MTF 50 has to be the baseline for measurement, so insisting we use MTF 0% of MTF 9% is asking me to make evaluations or apply mathematics to a very tiny percentage of photographers overall. (Assuming you don't actually have to pose that question...noise or subject?)


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## jrista (Oct 23, 2012)

Lee Jay said:


> Lee Jay said:
> 
> 
> > Lee Jay said:
> ...



The example you posted is not what you think it is. Multiple things changed between those two images. For other readers sakes, from the following link:

http://photos.imageevent.com/sipphoto/samplepictures/Pixel%20density%20versus%20teleconverters.jpg

Image 1: 
Optics: 70mm f/3.5
Sensor: 2.04 micron pixels

Image 2:
Optics: 280mm f/14
Sensor: 8.2 micron pixels

The physical lens and the sensor changed in those two sample images for the _express purpose_ of maintaining framing, which is not the same thing as what we are discussing here. In the context of your sample image, sensor resolution increased while focal length decreased. In the context of our discussion, sensor resolution either remains the same while focal length increases, or sensor resolution increases while focal length remains the same. We are discussing the following:

Camera A:
400mm lens + 2x TC
18mp Sensor with 4.3 micron pixels

Camera B:
400mm lens
36mp sensor with 2.15 micron pixels

And the question in context is: Is the output of those two systems the same?

The answer is NO. Simply adding a TC does not change the number of megapixels your camera has. It only magnifies the subject. The output of Camera A will be a PART of the subject, in high detail. The output of Camera B will be THE WHOLE subject, in high detail.



(Sorry for all the posts...damnable security block seems to trigger on large replies.)


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## RGomezPhotos (Oct 23, 2012)

Since I currently use the 5D2 for my fashion and portrait photography, I would need something that's a significant upgrade to make it worthwhile. The 5D3 is a great camera, but at the end of the day, isn't much of an upgrade from the 5D2. The 1DX is interesting but what am I buying? FPS. And that really doesn't matter much to me. A 50MP with 16-bit DR would be super. I think Canon could blow everyone, including MF manufacturers, out of the water if they put some real muscle in their R-D for this camera.

But this next camera will be a total pro camera and unless you're making lots of money from these pics, is not in the arena for most photographers.


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## swrightgfx (Oct 23, 2012)

jrista said:


> The answer is NO. Simply adding a TC does not change the number of megapixels your camera has. It only magnifies the subject. The output of Camera A will be a PART of the subject, in high detail. The output of Camera B will be THE WHOLE subject, in high detail.



One could always take multiple shots with the 2xTC and stitch together.  See: http://www.shen-hao.com/PRODUCTSabout.aspx?i=1012&id=n3 and DSC3212 on Vimeo.

EDIT: Video doesn't embed properly, so click the link at the bottom.


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## KitsVancouver (Oct 23, 2012)

Ray2021 said:


> As always we have descended into "I-need-120MP-on-a tiny area-cuz-I-can-argue-it-will-work".
> 
> Prior to the 1DX and 5D-III release, the same crowd (you know who you are, you have spent hours typing pages on here selling the same old 3 day old fish) screamed for 40+ MP and were bitterly disappointed when Canon went the low MP route for both bodies.
> 
> ...



Wasn't the 1Ds Mark III the flagship? Didn't it have higher MP than the rest of the cameras at the time?


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## sanj (Oct 23, 2012)

wickidwombat said:


> sanj said:
> 
> 
> > Am happy that this is in the 1d style bodies. As I believe such hi mpx is for hi end use and pretty useless for general photographers.
> ...



Ohh brotherrrrr!!!! Wow. THANK YOU so much for taking time to read my comment and clearly stating what you feel. 
As much as I wish, Elite I am not, but I will expand on my arrogant hogwash.
I believe 1d size body is that size for many more reasons than just a large battery. It gives it more processing power for things that matter to many (and nice things to have anyways): fps, shutter lag, VF blackout, duel cards, overall responsiveness etc.

Now, it would be awesome to have a high MP camera which is not totally to its potential because is it in a smaller size body. That's my point.

Further, all landscape photographers _generally_ need a tripod to create their masterpieces and as you mentioned it would be mounted on a tripod in the studio. So the size does not matter if a tripod is being used/carried anyways. 

In any case Canon will not design this camera based on what you or I think, they will make it best for the high mp. Hoping they have a super camera in 1d size body.

Regards!


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## wickidwombat (Oct 23, 2012)

sanj said:


> wickidwombat said:
> 
> 
> > sanj said:
> ...



eh ok i might have read your previous post the wrong way but it did sound a bit like keep it a 1D to keep the rif raf out kind of thing. sorry for giving you such a spray.

the bulk has no bearing on any of the 1D benefits, processing power can easily fit into a 5d sized body
VF blackout i love this on the 1D bodies wish i was carried over to the 5D
AF linked metering, more customiation ability
1 button press to enable bracketing - awesome there are so many 1D features that make it a 1D
only really have a 1D do you realise how much stuff the other models miss out on, stuff
however the time of the massive brick of a camera being the badge of honour showing that someone is a proffessional are long gone, some people use grips for legitimate reasons big hands, more comfortable for them, actually prefering to use the portrait shooting buttons.
many more use grips to try and look more impressive... 

I use my 1Dmk3 still because of the bombproof build and where i use it wont use another series camera because anything without the latest L weather sealing lenses or 1D build would have a very short lifespan.
however I would LOVE to have a small camera to use built to the same standard.
while I love my 5Dmk3 its not going to hold up to the punishment a 1D body can take

remember back in the day when there was a choice if your 1V had the extra bulk of the HS or if it was just a nice 1V if the 1DX was available sans grip i would buy one.

battery tech these days means they could easily have all the functionailty voltage processing power no mode dial wheel, the works in a gripless body


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## dlleno (Oct 23, 2012)

jrista said:


> dlleno said:
> 
> 
> > As for the question posed by PerfectSage, there does appear to be a real and practical answer, or at least rule of thumb, which would guide one towards the goal of advantaging all of that 116 lp/mm resolving power of the 7D sensor, and that is to choose optics that will present an image to the sensor with enough inherent detail. if the source image truly does not contain the detail, the sensor will not find any that isn't there. Whether or not that goal is a good one or not can be debated of course
> ...



very nice explanation Jrista, and the first coherant technical epistle I've seen here regarding the effects of lens choice as regards the resolving power of the sensor, both the contribution of individual components and the asymptotic behavior of the function. Essentially, the 1/(2 * RMS) method suggests that when one component in the system is replaced by one that is significantly worse than the previous aggregate, that the effects will probabaly be noticed. Moreover, the effect of such a substitution will be more noticeable with there are fewer components in the system. Accordingly, using the approximation of only two components (the sensor/lpf and the lens), one can easily see that the choice of lens will influence the overall resolving power of the system. Captain obvious, to be sure, but one could model the equation and see the effects (on end-2-end resolving power) of choosing one lens over another, an excersize left "to the reader", lol. . I suspect most would rather look at photos though


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## Panurus (Oct 23, 2012)

Thank you jrista. FTM50 is better that FTM 0%.

Why not to go a step further for the fun: FTM 100%? 

Let's see what is a contrast of 100%.
A picture of black and white lines, with a perfect optic, can for a particular spatial distribution give a contrast of 100%. In this case, the distribution is sinusoidal with min = 0 and max = 1.
http://www.flickr.com/photos/jeanrouck/6240117829#

The contrast value is there : 100% = ( 100 + 0 ) / ( 100 - 0 ) 
black is 100 and white is 0.
http://www.flickr.com/photos/jeanrouck/6240565328/#


For a FTM 50%, the darkest is 75%of grey and the brightest is 25 % of grey.
contrast : 50% = ( 75 - 25 ) / ( 75 + 25 )
So we are far away from the original black and white lines.

Remark : If Imax / Imin = 3 , the contrast is 50 %.
(100-33) / ( 100 + 33) = 50%
(75 - 25 ) / (75 + 25) = 50% 
(30 - 10 ) / (30 + 10) = 50%

Maybe , this pictures help to see (undestand) that the number of pixels will never change the grey pixels in white and black pixels. But one day, tools like the Richardson–Lucy deconvolution could help a little to find the original values and than more information will give better pictures. 


Zeiss do a good job about FTM: to read before dreaming about High MPx body.

Here is a picture with a part of the original sample, a 24Mpix pict of the sample and 12 Mpix pict of the sample..
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild13/$File/Bild_13.jpg
So you can see how a little black line is transformed, with a 12 MPx and a 24 MPx, in grey lines.


More informations about real lens:

http://www.zeiss.de/C12567A8003B8B6F/EmbedTitelIntern/CLN_30_MTF_en/$File/CLN_MTF_Kurven_EN.pdf

Measuring lenses objectively – Part 2
http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_31_MTF_en/$File/CLN_MTF_Kurven_2_en.pdf

Here are the pictures of the examples.
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild1/$File/Image_01.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_02.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_03.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_04.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_05.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_06.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_07.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_08.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_09.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_10.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_11.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_12.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_13.jpg
http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild14/$File/Bild_14.jpg

http://www.zeiss.com/C12578620052CA69/0/4FAB9EF851C018C5C12578D200405960/$file/cln_35_bokeh_en.pdf


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## symmar22 (Oct 23, 2012)

IF two sensors (39 and 50 Mpx) are out there, it could be they are planning release two cameras, one 39Mpx in a 5D type body (5Ds ?) that would be a competition for the D800, and later a 50Mpx camera in a 1D type body (1Dxs ?) to counter a future D4x(s).

This way everyone would be happy.

However I'd like to add my two cents about high res. cameras, and the fact that a lot of people seem to dismiss them on the pretext no one needs them, and 20Mpx are good enough for everything.

I can understand people are happy with their cameras and 18Mpx suit their needs, but some folks have other requirements. It's like if you would have said 20 years ago no one needs 4x5 or 8x10 cameras, 35mm is good enough for everyone. People who need high resolution sensors usually don't make 1000 pictures per day, it's about studio work, or architecture, or industrial photo, where quality is more important than quantity. When you work in a studio, you can spend hours on a setting before you even press the shutter, then all you need is a few frames, but with as much quality as you can deliver.

Nobody shoots wildlife or sports with a 4x5 camera, that doesn't mean 4x5 cameras were (are) useless for other styles of photography.


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## Lee Jay (Oct 23, 2012)

Mikael Risedal said:


> My good, you Jrista have great difficulties to discuss one thing at a time, you mixing apples with pears in a mess
> What are we discussing? how high resolution a good lens can resolve?, how many pixels we can have a benefit from??



The answer to that last question is infinity, except for limitations on the technical side of sensor design and production. Cell phone sensors are down to 1.25 micron pixels or so which would equate to 28,800x19,200 or 553 megapixels on a full-frame sensor, so the current limitation isn't on the technical side of sensor fabrication for large sensors. Eric Fossum (the guy that invented the active pixel CMOS sensor) believes we'll have gigapixel sensors in our lifetimes.


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## Lee Jay (Oct 23, 2012)

jrista said:


> Lee Jay said:
> 
> 
> > jrista said:
> ...



Yes, that is the subject we are discussing - is there a point to smaller pixels given the lenses we have available, to which the answer is obviously "yes", as can be shown by simple math and by examples from TCs which show you what the center of the image would look like with smaller pixels.



> If you are referring to optical system resolution, rather than spatial resolution, then I agree. However you keep applying the units "lp/mm" to system resolution, which feels like a major conflation to me. Assuming the optical spatial resolution of the entire lens setup (original lens + TC) remains the same (which is generally impossible when adding a TC, as it reduces your REALTIVE aperture, which implicitly means your optical spatial resolution of THE ENTIRE LENS SETUP is reduced), the final system _spatial_ resolution will be lower than that of the lens or the sensor, as it is the root mean square of the blur each individual component.



I can't even believe you just said that. So, adding a TC reduces optical spacial resolution? Better throw them all out then.

A TC doesn't change optical resolution.


> In the context of scientific astrophotography, the imaging devices used are orders of magnitude more expensive than a consumer-grade sensor.



Which is irrelevant since I was talking about using $50 Walmart webcams for astro imagining. Or, if you want to go high-end, something like a Flea-3, which is a better version of the same thing.



> Lee Jay said:
> 
> 
> > > The notion that a camera can usefully resolve anything at MTF 9% (Reighley) is also pretty ridiculous.
> ...


Better ask Damian (one of the best amateur planetary imagers in the world) why he shoots 5.6 micron pixels at f/30 instead of his scope's native f/11:

http://www.damianpeach.com/best.htm

Look, the facts are simple. If you want to see how a particular lens would perform on a camera with four times as many pixels as your current camera, simply add a good quality 2x TC and see for yourself how the center of that hypothetical sensor would look with the bare lens. Period.


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## K-amps (Oct 23, 2012)

LetTheRightLensIn said:


> K-amps said:
> 
> 
> > LetTheRightLensIn said:
> ...



Good point: I doubt ripples will be that consistent to fool the demosaicing algo's... Leaves probably not, they are too random, and jagged rocks too... not saying it is impossible, just saying it will be too far between to be an issue. OTOH I could gain some resolution without the AA filter in the way... rest will be PP'ed. 
I don't shoot video... so PP'ing stills is not a huge deal for me...


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## dlleno (Oct 23, 2012)

Lee Jay said:


> I can't even believe you just said that. So, adding a TC reduces optical spacial resolution? Better throw them all out then.
> 
> A TC doesn't change optical resolution.



Lee Jay -- are you really saying that the TC will not introduce diffraction artifacts due to the change in aperture, and that the additional glass elements will present or expose no further optical abberations in the image presented to the sensor? Please do explain the conditions under which modifying the optical system by adding a piece of glass cannot change it's optical resolution properties.


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## Lee Jay (Oct 23, 2012)

dlleno said:


> Lee Jay said:
> 
> 
> > I can't even believe you just said that. So, adding a TC reduces optical spacial resolution? Better throw them all out then.
> ...



First one yes, second one no.

Diffraction (angular resolving power of the optical system) goes with aperture, not f-stop. That's why telescopes are sold by aperture and not by focal length and f-stop (well, light gathering does as well and that's the second reason telescopes are sold that way). The only reason f-stop was in the formula I posted was because that wasn't angular resolution of the optical system (which is what we're really after), it was spatial resolution at the sensor.

sin theta = 1.22 * lambda / D where D is the diameter of the lens' aperture. A teleconverter doesn't change D and so it doesn't change theta.

http://en.wikipedia.org/wiki/Angular_resolution

I already said TCs are actually slightly worse than small pixels because of aberrations. Fortunately, TCs are close to optically perfect these days so the degradation is quite small. Regardless, this works in favor of my argument - a TC will give a good simulation of how a lens would perform on smaller pixels. In fact, the smaller pixels will perform better so this TC test is a worst-case.


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## jrista (Oct 23, 2012)

Lee Jay said:


> jrista said:
> 
> 
> > You are only thinking pixel size, which I guess is one way to look at it.
> ...



No, the topic we were discussing is whether adding a TC is exactly the same and just as good as using a sensor with a higher pixel density by the same factor as the TC added. Its a bit more complex than simply stating "well we are just talking about pixel size".



Lee Jay said:


> > If you are referring to optical system resolution, rather than spatial resolution, then I agree. However you keep applying the units "lp/mm" to system resolution, which feels like a major conflation to me. Assuming the optical spatial resolution of the entire lens setup (original lens + TC) remains the same (which is generally impossible when adding a TC, as it reduces your REALTIVE aperture, which implicitly means your optical spatial resolution of THE ENTIRE LENS SETUP is reduced), the final system _spatial_ resolution will be lower than that of the lens or the sensor, as it is the root mean square of the blur each individual component.
> 
> 
> 
> ...



YES, adding a TC reduces optical spatial resolution, because it reduces the RELATIVE APERTURE. Diffraction is dependent on aperture. For a small table, so we all (you, me, and other readers) have the same reference information:


Diffraction-Limited ApertureMTF 50 (lp/mm)f/1691f/1.4494f/2346f/2.8247f/4173f/5.6123f/886f/1163f/1643f/2231

If you start out with an f/4 lens, without a TC your lens could achieve up to 173lp/mm, if it was diffraction limited. A non-diffraction limited lens, one which is aberration limited, would have LESS spatial resolution due to the blurring caused by aberrations. If you add a 2x TC to that f/4 lens, regardless of what the focal length ends up being, the aperture is now f/8. That explicitly limits you to 86lp/mm optical spatial resolution on the upper bound, assuming you are, again, diffraction limited, and not aberration limited. 

So YES, adding a TC has the effect of REDUCING MAXIMUM POTENTIAL SPATIAL RESOLUTION. Its physics. There is no way around that fact. 

What you are referring to is magnification. Adding a TC enlarges the subject, so the portion of the subject that is projected through the lens and onto your sensor is LARGER. It would be similar to moving 1.4x or 2x closer to your subject without the TC...except that if you move closer rather than adding a TC, your relative aperture remains larger, which means the upper bound on spatial resolution remains higher.

I don't know how else to explain it, but magnification and spatial resolution are disjoint. You can technically increase subject magnification without changing your spatial resolution. You could also increase your spatial resolution without magnifying your subject. The two are independently variable. Examples of achieving each optically:

1. Double magnification while maintaining spatial resolution:
- Swap a 400mm f/4 lens for an 600mm f/4 lens. 
- Same relative aperture, 2.25x larger subject.
- Subject size in-frame is relative to the square of the ratio of the focal lengths: (600/400)^2 = 1.5^2 = 2.25
2. Double spatial resolution while maintaining magnification:
- Swap a 400mm f/8 lens for a 400mm f/4 lens
- Same subject size, double the relative aperture
- Diffraction-limited spatial resolution increases from 86 lp/mm to 173 lp/mm
3. Quadruple magnification while halving spatial resolution:
- Add a 2x TC to a 400mm f/4 lens
- Half the relative aperture, 4x larger subject
- Diffraction-limited spatial resolution drops from 173lp/mm to 86lp/mm
- Subject size in-frame is relative to square of the ratio of the focal lengths: (800/400)^2 = 2^2 = 4

As you can see, despite losing spatial resolution with a TC, adding a 2x TC QUADRUPLED the size of your subject relative to the same sensor frame. You doubled the amount of resolved detail, despite the loss in spatial resolution...thanks to magnification. 



Lee Jay said:


> > Lee Jay said:
> >
> >
> > > > The notion that a camera can usefully resolve anything at MTF 9% (Reighley) is also pretty ridiculous.
> ...



Sure...but you've just invoked cropping. Who buys a 500mp sensor to crop out the middle 18mp? Let's stop equivocating here. There is a huge difference between quadrupling pixel density in a FF sensor, and adding a TC. With the TC, you only get the center 25% crop. With a FF sensor with quadruple the density, *you get the whole subject.* Equivocating by saying something along the lines of "My 400mm lens with a 2x TC is the same as having a 369mp sensor" is a fallacy. The 369mp sensor is capable of resolving a 4x more area of your subject with the same amount of detail as the 2x TC. That is a HUGE difference. That is a full two orders of magnitude difference. 

The terminology you use in your approach to explain what a TC is doing for you is misleading. You are not increasing spatial resolution, which is what it sounds like you are doing when you equate the effect of magnification offered by a TC to using a higher density sensor of the same physical dimensions. You are *magnifying your subject* at a *lower spatial resolution*. The math here isn't all that complex. Apertures, diffraction, spatial resolution, magnification. It's all pretty basic, and no amount of wordmincing and dancing around the heart of the debate will get you past the facts. 

* TC's magnify. 
* Higher density sensors resolve more. 

Two very different things.


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## jrista (Oct 23, 2012)

Lee Jay said:


> dlleno said:
> 
> 
> > Lee Jay said:
> ...



First, telescopes are marketed by their physical aperture dimensions because they only have a a fixed aperture. The aren't like a photography lens, where the aperture is adjustable. There is no need to market telescopes in any other way because any other way simply doesn't apply.

You are misunderstanding what a TC does. A teleconverter is a magnifying glass. It simply enlarges what the original lens projects. It magnifies everything....including diffraction. You cannot add a TC to a lens an not increase the effects of diffraction, despite the facts you just described above. Here is another formula, for the physical size of an airy disc:


```
D = 2.44 x λ x f#
```

Note the fact that the RELATIVE APERTURE, or FOCAL RATIO, is what matters here...not the size of the entrance pupil. The size of an airy disc is of intrinsic importance to diffraction's effects *at the sensor.* The size of an airy disc is dependent on F-Number, which means the addition of a TC most definitely has an impact on spatial resolution, since it will increase F-Number by the same factor as the TC used (f/4 * 1.4 = f/5.6; f/4 * 2 = f/8, f/5.6 * 1.4 = f/8, etc.) 

BTW, my formula above...it comes from the same wiki page you linked. Just a little farther down below angular resolution is the description of spatial resolution:



> A similar result holds for a small sensor imaging a subject at infinity: The angular resolution can be converted to a spatial resolution on the sensor by using f as the distance to the image sensor; this relates the spatial resolution of the image to the f-number, f/#:
> 
> 
> ```
> ...


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## K-amps (Oct 23, 2012)

Jrista... I usually gloss over your techno rant...  But the last post (with the DLA MTF table) was well constructed and easy to follow for peeps like me. Thanks!


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## jrista (Oct 23, 2012)

K-amps said:


> Jrista... I usually gloss over your techno rant...  But the last post (with the DLA MTF table) was well constructed and easy to follow for peeps like me. Thanks!



Glad to be of service.


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## Lee Jay (Oct 23, 2012)

jrista said:


> Lee Jay said:
> 
> 
> > jrista said:
> ...



Yes, that's what I said.



> Lee Jay said:
> 
> 
> > > If you are referring to optical system resolution, rather than spatial resolution, then I agree. However you keep applying the units "lp/mm" to system resolution, which feels like a major conflation to me. Assuming the optical spatial resolution of the entire lens setup (original lens + TC) remains the same (which is generally impossible when adding a TC, as it reduces your REALTIVE aperture, which implicitly means your optical spatial resolution of THE ENTIRE LENS SETUP is reduced), the final system _spatial_ resolution will be lower than that of the lens or the sensor, as it is the root mean square of the blur each individual component.
> ...



Wrong, and right - diffraction is based on aperture, not relative aperture.

http://en.wikipedia.org/wiki/Rayleigh_criterion#Explanation

sin theta = 1.22*lambda/aperture diameter

You're conflating resolution at the sensor in lp/mm (which is largely irrelevant) with optical angular resolution (which is what we care about - what details in the scene can be resolved).

Look, the facts are simple. If you want to see how a particular lens would perform on a camera with four times as many pixels as your current camera, simply add a good quality 2x TC and see for yourself how the center of that hypothetical sensor would look with the bare lens. Period.


> Sure...but you've just invoked cropping. Who buys a 500mp sensor to crop out the middle 18mp?



I do, as do many others. If you have a better way to simulate the performance of our current lenses on a hypothetical and not-yet-built higher-pixel-count sensor than using TCs and our current sensors, please cough it up. And I don't mean buying a $50,000 lens projector, I mean using stuff I actually have.


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## jrista (Oct 23, 2012)

Lee Jay said:


> You're conflating resolution at the sensor in lp/mm (which is largely irrelevant) with optical angular resolution (which is what we care about - what details in the scene can be resolved).



It can't be irrelevant...because the resolution AT THE SENSOR is WHAT THE SENSOR cares about (and therefor, what I care about in the context of this discussion.) Spatial resolution of the *real image* (the projection of the lens at the _focus_, no focal, plane...at the sensor's surface) is exactly relevant when discussing what a sensor is actually resolving and registering, and what is converted into a digital image by the ADC, as compared to what a TC is doing to that very same *real image*. The ability of a lens to discern detail at the focal plane, in the *virtual image*, is not in the context of the discussion here. The focal plane could be twenty feet away, it could be a thousand feet away, but that won't change the spatial resolution of the real image projected by the lens onto the sensor.

I think your inverting the problem, and thinking about everything exterior to the camera. Spatial Resolution of the image projected by the lens onto the focus plane (which exists INSIDE the camera AT the sensor) is quite explicitly what I am referring to. I don't see how you could logically discuss anything else when comparing the effects of magnification by a TC in relation to increasing sensor spatial resolution...all of that exists inside the camera, behind the aperture, not outside in the real world relative to the front element of a lens or its entrance pupil.


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## TheSuede (Oct 24, 2012)

You are seriously talking past each other now, and things are mixed up beyond belief.

Disregarding the real-world effects of a TC _(increased reflection and absorption losses, decrease in sharpness due to optical imperfections)_ from now on through this entire post: Yes, of course a TC magnifies the diffraction circle by exactly the same amount as the rest of the image. But that is also the point; the object referred diffraction is already determined at the front of the optical system, by the entrance pupil _(as long as we're within reasonably Gaussian systems, for microscopes and other applications with very high magnification you need to look at angular aperture in stead of numerical aperture)_. A teleconverter will magnify both this object referred diffraction and target detail, a wide-converter will decrease magnification on both diffraction and target detail. It varies the projected image magnification and not the angular object referred diffraction, which is what optically limits your target resolution.

[quote author=jrista]
You are misunderstanding what a TC does. A teleconverter is a magnifying glass. It simply enlarges what the original lens projects. It magnifies everything....including diffraction. You cannot add a TC to a lens an not increase the effects of diffraction, despite the facts you just described above.
[/quote]

What YOU forget to mention in your little maths excursion under the qouted text above is that the f/# number also implicates that you have a reproduction scale. This indicates both that you're within Gaussian optics rules (as opposed to in microscopy, where angular aperture is the metric used) and that you have an Airy disc diameter that is constant with f/# on the image plane. A 50mm used on f/11 will give the same Airy disc size on the sensor as a 100mm f/11 used on teh same sensor.

But the target magnification (reproduction ratio) is twice as high on the 100mm option, so you have:
-same Airy disc size on the sensor
-twice the reproduction ratio!

This means that if you shoot a side view of say "a car" from a distance where 50mm would give you a car length of 500 pixels on the image and a diffraction effect of maybe 3 pixel widths, using the 100mm lens at f/11 would give a car size on the sensor of 1000 pixels, but still a diffraction effect of 3 pixels - and that means that you've halved the diffraction effect on the car, i.e halved the angular object referred diffraction. Doubled the optically limited usable target resolution - since you doubled the entry pupil size.... (50/11 = 4.5mm pupil, 100/11 = 9mm pupil)

Diffraction and Airy disc size are linearly scaled by the same constant since the angular diffraction in front of the lens depends on the entry pupil diameter and nothing else (until you hit the Gaussian model limit, see angular aperture). If the airy disc covers, say, a one inch detail on an object far away, the SAME one inch detail will be covered by the exact same relative Airy disc, no matter what magnification/resolution you inspect the projection with in the image plane.

This isn't actually very hard to see in reality (_most of us do have a zoom lens available I suppose?_)
Take one shot at say *100mm and F11* of a distant object. With the same camera, directly after that take another shot aimed at the same target from the same distance, but now with *200mm and F22*. They both have the same entrance pupil diameter (9mm), and they're both into diffraction limited range on most modern sensors.

Which of the two will have the highest target resolution?
Since one has twice the target reproduction ratio or magnification we need to either downsample the 200mm image or upsample the 100mm image to compare them at equal size presentation. And unless your aperture calibration is seriously off on the lens you use, the 200mm F22 shot will have equal or better target resolution!

*Don't doubt, try for yourself.*

In astro (which is a purely Gaussian limited application with ordinary systems, with infinity focus targets) this is extremely important, since the angular resolution in front of the lens is determined by the entrance pupil. NOTHING you do behind that can make things better, in any way. It doesn't matter what focal length you use, the entrance pupil determines how small the (infinity distance) details you can accurately resolve optically is. Within practical limits of course, but this depends more on lens manufacturing and smallest available pixel size with good performance. You won't find many spectacularly detailed shots of the moon taken with a 24mm lens.

Keeping the entrance pupil constant: If you use a shorter focal length you get a smaller reproduction ratio, and you need smaller pixels to accurately resolve the optical projection image. Use a longer focal lens, and you can use larger pixels. It will not in any way have an effect on the object space angular resolution of the system, you just adapt the sensor resolution to fit the optical resolution.

So: You get the same optical far-field target resolution (again using the elusive "perfect" TC) if you use a 400/4.0 with 2x TC, as if you use an 800/8.0 on the same camera, or indeed as you do if you use a 400/4.0 on a half size (quarter area) sensor with the same amount of pixels. Diffraction limitation of the target does not change, light energy per pixel captured per second does not change.


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## jrista (Oct 24, 2012)

TheSuede said:


> You are seriously talking past each other now, and things are mixed up beyond belief.
> 
> Disregarding the real-world effects of a TC _(increased reflection and absorption losses, decrease in sharpness due to optical imperfections)_ from now on through this entire post: Yes, of course a TC magnifies the diffraction circle by exactly the same amount as the rest of the image. But that is also the point; the object referred diffraction is already determined at the front of the optical system, by the entrance pupil _(as long as we're within reasonably Gaussian systems, for microscopes and other applications with very high magnification you need to look at angular aperture in stead of numerical aperture)_. A teleconverter will magnify both this object referred diffraction and target detail, a wide-converter will decrease magnification on both diffraction and target detail. It varies the projected image magnification and not the angular object referred diffraction, which is what optically limits your target resolution.
> 
> ...


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