# Why I need MPs



## thepancakeman (Dec 10, 2011)

Just because I like to throw fuel on the flame...

There are so many discussions about needing more megapixels with strong proponents on each side, I thought I'd join the fray with some specific examples (especially because it seems like most of the "I need MPs" side is landscape photographers of which I am most definitely not.)

Below I am posting the crop image and then the original. Again, my context is that capturing a decent shot of every athlete in the race is my number one priority. There is little to no time to worry about doing anything artistic, and often even a basic reframing of the shot is more work that I seem to have time for. So some of these are cropped because I think there is artistic value in the a portion of the original image (and 500 shots of "runner...runner...runner...runner" gets old without some creativity : ), or as one example shows, simply to isolate the given athlete.

I'm open to contructive criticism if there are things I could do differently to reduce or eliminate my "need" for more MPs (or any other photographic/artistic feedback).


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## thepancakeman (Dec 10, 2011)

And for the originals...


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## Mt Spokane Photography (Dec 10, 2011)

Don't you actually want higher resolution and more detail? And, you believe that you get that from more MP's? Due to the effects of lens diffraction, you reach a point where smaller pixel size does not yield more resolution or detail. Once you reach that, then a move to A larger format with the same sized photosites will allow for more Resolution and Detail. The point where this happens for a f/2.8 lens is claimed to be at about 4.2 microns. Beyond that, its just merely salesmanship.

Unfortunately, the step from crop to FF is expensive, and to MF even more expensive, since new lenses are required as well as a large sensor.

If you are making money from landscape photography, perhaps your work will pay for a move. If its for personal use, your finances are going to determine that. One thing that is not overcome yet by current technology is a way to overcome lens diffraction. 

However, they are lots of researchers working on new ideas to get around the issue. We will see breakthrus over the next 20 years that will blow away todays technology, but they are not nearly ready to start production.

Here is a video of a lecture given by Eric Fossum, one of the CMOS sensor inventers. He covers current state of camera sensors and where some of the research is heading.

He is not very kind to companies that mislead photographers to purchase cameras with more MP.

http://www.dpreview.com/news/2011/10/28/ericfossumspeech


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## thepancakeman (Dec 10, 2011)

Mt Spokane Photography said:


> Don't you actually want higher resolution and more detail? And, you believe that you get that from more MP's?



Okay, maybe I'm confused, but aren't higher resolution and more megapixels the same thing? ???



> Due to the effects of lens diffraction, you reach a point where smaller pixel size does not yield more resolution or detail.



There seems to be some debate as to whether we have reached the diffraction limits of current lenses at 18ish MPs, but I'm not really looking to debate the _technical feasbility_ of it. I'm asking whether or not an increase in MPs would increase my ability to get printable results in my circumstances or if there are simply usage/technique changes that I need to make. Some of these crops are all the way down around 1200x800 which is questionable for even a 5x7 print.



> If you are making money from landscape photography, perhaps your work will pay for a move. If its for personal use, your finances are going to determine that.



I think I'm hopeless as a landscape photographer even if I wanted to be one. :'( As it is, I'm just earning enough to "support the habit" doing sports event photography.


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## dirtcastle (Dec 10, 2011)

I've been wondering about this too.

For the sake of communication, maybe we could talk about this issue in terms of "detail" and "output size". The term "resolution" seems ambiguous to me.

Where is the megapixel threshold for detail on a full frame camera? At what megapixel count on a FF does detail stop improving? 

What about the issue of cropping? Let's say I take the same image with a FF 10MP and 20MP. Are people suggesting that I can simply upsize the 10MP (using post software) and it will have the equivalent detail as the 20MP shot ??


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## Denabears (Dec 10, 2011)

Best if everyone makes up their own mind on this based on looking at large prints, but second best is evidence from some of the lens testing sites. 

The first error people make is bringing diffraction into discussions like this (particularly along with misuse of the word "limit"). Diffraction is not a function of pixel size - as a property of the lens how could it possibly be so? 

Take a look at Photozone.de, where some Canon lenses were tested on 8Mpixel and 15Mpixel cameras. Of course we don't know for sure that the corresponding tests were of the very same lens (probably not in most cases), but if you look at all such cases you should become convinced that whether at f/2.8 or f/11 the MTF50 scores are higher with the 50D - athough they are not higher by as much as square root (15/8) = 1.37. Take the 85/1.8 where at f/8 it is almost certainly a diffraction limited lens (all that means is diffraction is greater than all the other sharpness-reducing aberrations at that f no.). On the 350D it measures 1980 lp/ph in the center, while on the 50D the score is 2372, 1.2 times larger. Now we cannot be sure how much of the shortfall over the theoretical increase is due to the lens, and how much due to the camera (but none is due to diffraction which is exactly the same in these two cases). 

Another way to look at the question is to go to dxomark.com, and pick a nice lens. If we take the 85/1.8 again and look at the MTF (measurement tab, resolution, MTF) it is about 10% contrast at 80 lp/mm in the center (on full frame, but here we want to get a lower limit for the lens). That is with a 21Mpixel sensor and its AA filter, so the lens has much higher contrast and resolution (we can only guess by how much). Note the figure changes little for RGB or f no. settings. 

So *at very minimum* this lens resolves 80 lp/mm (and probably way beyond, possibly as much as 200 lp/mm, but I can't prove that). Since the AA filter is imperfect it is best to have slight "oversampling", say 3 blue (6 green) pixels per cycle, or 6x80 pixels per mm. That means that a sensor with (6x80x24)x(6x80x36) will be guaranteed to be getting useful information from the lens, that's 200Mpixel on full frame, or 80Mpixel on APS-C. Don't take the actual number too seriously, the point is that even with this pessimistic assessment of lens performance, there is most definitely scope for getting better results, admittedly in the face of rapidly diminishing returns (increasing the pixel count by a factor of 4 will only increase the resolution by a few tens of percent - but one day it will become cheap enough to allow that in a fast camera).

Of course some people who judge sharpness on "100%" images on a monitor won't believe any of this, but look at large prints and decide yourself.


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## niccyboy (Dec 10, 2011)

Nice shots. Love the crop on the first image.


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## Gothmoth (Dec 10, 2011)

learn composition in camera.
that will give you more details then cropping bad shots afterwards.

now you will say "often i canÂ´t get close enough for the right composition".
well i say better spend your money on a tele instead of a 36MP camera. 



> The first error people make is bringing diffraction into discussions like this (particularly along with misuse of the word "limit"). Diffraction is not a function of pixel size - as a property of the lens how could it possibly be so?



well.... first error is that you have no clue what you are talking about.
of course itÂ´s a matter of "pixel size". when the airy disc is bigger then a photosite you canÂ´t resolve more then the airy disc size. that makes smaller photosites useless at some point (size).
and because itÂ´s a physical limitation of LIGHT you canÂ´t do much about it.

if this limit is reached yet.. that is a complete other discussion!!

some will argue that with an bayer sensor you will get more accurate colors of an given pixel, when the photosites are smaller then the airy disc..... but more accurate color does not translate into better resolution. even when you agree to that and think it makes a visible difference in color accuracy.. at some point this effect will also be gone on a bayer sensor.

the lens is one limiting factor for resolution, affected by diffraction the other is the size of the photosites on the sensor. thatÂ´s a fact.. period.

im to bored to explain it again have a look here:

http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

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


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## neuroanatomist (Dec 10, 2011)

Gothmoth said:


> learn composition in camera.
> that will give you more details then cropping bad shots afterwards.
> 
> now you will say "often i canÂ´t get close enough for the right composition".
> well i say better spend your money on a tele instead of a 36MP camera.



OP needs to capture every athlete in the race. Not sure what the distribution method for the photos is, but in the two uncropped shots of the runners, you can see their race numbers - that might be necessary and might preclude tight composition with limited time. I'm sure there are workarounds, but just pointing out one other factor.


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## wellfedCanuck (Dec 10, 2011)

neuroanatomist said:


> Gothmoth said:
> 
> 
> > learn composition in camera.
> ...



That's the only reason atheletes wear numbered bibs. Everything else is in an rfid chip that's usually tied to our shoelaces. The photogs pick a spot along the race course and make the best of whatever comes their way. The results usually aren't pretty...  Participants pay $40-$80 for their race photos to whatever company has contracted the event although I'm not sure what each invidual photographer nets.


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## Denabears (Dec 10, 2011)

Gothmoth said:


> well.... first error is that you have no clue what you are talking about.
> of course itÂ´s a matter of "pixel size". when the airy disc is bigger then a photosite you canÂ´t resolve more then the airy disc size. that makes smaller photosites useless at some point (size).
> and because itÂ´s a physical limitation of LIGHT you canÂ´t do much about it.
> 
> the lens is one limiting factor affected by diffraction, the other is the size of the photosites on the sensor. thatÂ´s a fact.. period.



Perhaps you wrote in haste. 

The diffraction from the lens does, of course, produce a slightly fuzzy (unsharp) representation of the image on the sensor. This fuzziness in the focal plane does, *by no means* depend on anything to do with the sensor. In fact the fuzziness is exactly the same whether there is a sensor there or not e.g. if film were used.

Equally obvious is that if you choose to scale the picture according to pixel size the fuzziness will appear greater because you scale it more with smaller pixels - but in reality it did not change.

Note that you will never see an Airy disk in a real photograph unless you photograph point sources. Note too that the site you cite, thanks, needs very careful reading, but if carefully read comes quite close (from an author who does not appear to be an expert) with what I said (read right to the very end "Are smaller pixels somehow worse? Not necessarily ..."). 

Anyway, what stands beyond doubt is the range of results available for anyone to inspect at DXOmark etc. already given. Choose your sampling requirements based on sound information theory, and calculate where you want to place your resolution limit.


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## neuroanatomist (Dec 10, 2011)

Denabears said:


> Gothmoth said:
> 
> 
> > the lens is one limiting factor affected by diffraction, the other is the size of the photosites on the sensor. thatÂ´s a fact.. period.
> ...



Perhaps you read in haste.

Your first statement: diffraction depends only on the lens, and the detector is irrelevant. 

His response: both lens and detector impact diffraction. 

He's correct, but *by no means* are you correct.


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## Zuuyi (Dec 10, 2011)

Gothmoth said:


> learn composition in camera.
> that will give you more details then cropping bad shots afterwards.
> 
> now you will say "often i canÂ´t get close enough for the right composition".
> well i say better spend your money on a tele instead of a 36MP camera.



So the OP is supposed to compose 8 different pictures, of different objects, who are moving 10-30/mph(runner vs. biker), in a matter of a few seconds. 

How about you try to take 8 different pictures of 8 different stationary(not even moving like the OP) targets in just 5 seconds. Then you tell me how that went.


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## Orangutan (Dec 10, 2011)

Pancakeman, perhaps you're just asking too much of one camera. It appears that your work is largely "mechanical:" find the location, compose for the scene (rather than for the actual subjects) then hit the shots. Maybe you could assemble a rig with 2 or 3 cameras mounted on it, and fire all at once. If you have that mounted on a tripod or monopod, you might also keep a single body free for more creative composition. Yes, a lot more expensive gear, but also a lot more useable shots.

And one more idea: maybe buy a 1DX and use it in video mode. The video resolution might be high enough to let you "sweep" a group and get multiple useable still shots.

I have no idea if this would actually work for the particulars of your work environment, but thought I'd throw it out there.


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## markIVantony (Dec 10, 2011)

The OP, by my interpretation, is asking about cropping ability with larger MP. The answer of course is yes.

So then here comes the laws of physics:



Gothmoth said:


> if this limit is reached yet.. that is a complete other discussion!!
> ...
> im to bored to explain it again have a look here:
> http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm



For those persons who add technical aspects to this type of discussion, the fact that you get bored repeatedly explaining it, or have to continually rehash the same arguments, means it is probably not explained well enough for the average layman.

Reminding us that airy disc and diffraction are overriding limitations are good, but what would REALLY help (me) is real-world examples that drive it home, such as:
- The MP limit on a FF sensor with EF70-200mm f/2.8 would be .....

Is it possible to define in those terms? I don't even know if it works that way. In my mind, I do somewhat grasp the great technical commentary given, but these discussions will be endless (which is not necessarily a bad thing...I usually learn something) without practical examples. **If I were capable, I would try. Perhaps a parable would do


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## Denabears (Dec 10, 2011)

neuroanatomist said:


> Perhaps you read in haste.



I don't believe so. But I certainly don't want to get into an endless argument either as I doubt it would help anyone. 

I look forward to perhaps 10 years from now when 100+Mpixel cameras will be available, fast and cheap,until then we can but dream (or stitch, but not so much for sports photographs).


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## ferdi (Dec 10, 2011)

Firstly remember what is expected of you. Practice composition in camera so you don't have to crop in post because this takes forever for a few thousand pictures. If the client wants to publish any pictures he will crop them anyway, and usually not very artistically.

For your own portfolio, pick a few of the best and edit these more thorougly, including crop, angle, spot removal, vignette, etcetera. 10 MP should still be enough for a web portfolio and smaller prints (up to A4). If not then your upcoming 7D might be the right solution for you; I would have suggested renting it otherwise.


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## Mt Spokane Photography (Dec 10, 2011)

Denabears said:


> Best if everyone makes up their own mind on this based on looking at large prints, but second best is evidence from some of the lens testing sites.
> 
> The first error people make is bringing diffraction into discussions like this (particularly along with misuse of the word "limit"). Diffraction is not a function of pixel size - as a property of the lens how could it possibly be so?



Do use a camera without a lens?? The diffraction properties of a lens are part of the camera system, and affect the final result. There is not a "Limit", its a gradual effect. 

You can have a 100mp sensor and get 100mp files, but the resolution will be limited by the lens and lens aperture.


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## distant.star (Dec 10, 2011)

I second this emotion.

I like looking at your finished pictures. Good work.




niccyboy said:


> Nice shots. Love the crop on the first image.


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## dirtcastle (Dec 10, 2011)

The original question here is not about cropping.

The question is whether increased megapixels increase the ability to crop without losing detail.

I've read the responses and now I'm more confused.


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## neuroanatomist (Dec 10, 2011)

Denabears said:


> But I certainly don't want to get into an endless argument either as I doubt it would help anyone.



Well, if you believe that the sensor characteristics play no role in determining the effect of diffraction on an image, it definitely would be endless... Can you provide some documentation or evidence that the pixel density of the sensor has no effect on the aperture at which diffraction affects image sharpness?


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## Canon-F1 (Dec 10, 2011)

neuroanatomist said:


> Well, if you believe that the sensor characteristics play no role in determining the effect of diffraction on an image, it definitely would be endless... Can you provide some documentation or evidence that the pixel density of the sensor has no effect on the aperture at which diffraction affects image sharpness?



of course he can not.
but some people would even argue that they can build a spaceship thatÂ´s faster then light.

i mean what is so complicated to understand?
everyone with some school education that includes math can look at the wikipedia link and see that what is written there itÂ´s correct.



> Cameras
> 
> If two objects imaged by a camera are separated by an angle small enough that their Airy disks on the camera detector start overlapping, the objects can not be clearly separated any more in the image, and they start blurring together. Two objects are said to be just resolved when the maximum of the first Airy pattern falls on top of the first minimum of the second Airy pattern (the Rayleigh criterion).
> Therefore the smallest angular separation two objects can have before they significantly blur together is given as stated above by
> ...


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## Canon-F1 (Dec 10, 2011)

> Perhaps you wrote in haste.
> 
> The diffraction from the lens does, of course, produce a slightly fuzzy (unsharp) representation of the image on the sensor. This fuzziness in the focal plane does, *by no means* depend on anything to do with the sensor.



well you donÂ´t know what we are talking about.

the fuzziness does not depend on the sensor sure.... nobody said it does.
but the RESOLUTION is limited when the airy disc is bigger then the photosites.
and the photosites depend on the sensor. 

the bad thing is he gave you TWO links to get some infos.... but you seem to ignore it.

the lens (the lens design) has nothing to do with the resolution limit on sensor level.
it depends on the aperture and the wavelength of the light ONLY.
for this we assume a PERFECT lens.... so no negative effects by lens design (imperfections).

so even in 100 years you will still be bound by this simple rule of physics.
because you canÂ´t build a better lens then a PERFECT lens. 

the only thing a REAL lens does it to make the diffraction effect WORSE.
but ultimately at some photosite size you canÂ´t resolve more details even with a physical and mathematical PERFECT lens. 

to resolve more details you have to go to smaller wavelengths (smaller then visible light).

when you look at at this link: http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

you should see why smaller photosites can not resolve more information then the size of the airy disc. 



> In fact the fuzziness is exactly the same whether there is a sensor there or not e.g. if film were used.



thatÂ´s correct but you have to think it through!
no matter if FILM or a DIGITAL SENSOR, when aperture and wavelength combination create an airy disc thatÂ´s bigger then a photosite or a grain on film, then you canÂ´t resolve more then that size of the airy disc. because there is not more INFORMATION.

ergo... at some point, independend from lens quality, more megapixel (smaller photosites) on a sensor will not result in better resolution.



> Note that you will never see an Airy disk in a real photograph unless you photograph point sources.



you should read the articles again. : 
this one sentence shows your lack of understanding.
the first sentences in the wikipedia article should give you an hint:



> "In optics, the Airy disk (or Airy disc) and Airy pattern are descriptions of the best focused spot of light that a perfect lens with a circular aperture can make, limited by the diffraction of light.
> 
> The most important application of this concept is in cameras and telescopes. *Owing to diffraction, the smallest point to which a lens or mirror can focus a beam of light is the size of the Airy disk.* *Even if one were able to make a perfect lens, there is still a limit to the resolution of an image created by this lens.* An optical system in which the resolution is no longer limited by imperfections in the lenses but only by diffraction is said to be diffraction limited."


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## Denabears (Dec 10, 2011)

neuroanatomist said:


> Can you provide some documentation or evidence that the pixel density of the sensor has no effect on the aperture at which diffraction affects image sharpness?



Let me try this argument, which I hope is based on assumptions that we can agree on. 3 points make the argument (which is by no means original):

1) The sharpness, more precisely the MTF, of the system (camera+lens) can be expressed as the product of exactly 3 factors: 
_a_) MTF curve describing lens aberration excluding diffraction,
_b_) MTF curve diffraction (not quite a simple as the correct formulae kindly given by Canon-F1 would suggest)
_c_) sensor MTF. 
Note: as usual for MTF curves _a_, _b_ and _c_ are all functions of spatial frequency (normally declining with frequency).

2) _a_ and _b_ are functions of the aperture (as well as spatial frequency). We all know that factor _a_ usualy improves as the lens is stopped down quite quickly at first, then more slowly (from f/4 or so for most decent lenses).
We also all know that factor _b_ follows the inverse relationship hinted at by Canon-F1's Rayleigh criterion - but that is only one point on the curve. I suspect the most important point is that some (perhaps little) contrast remains to much higher spatial frequencies (and yes, there are nulls where there is no contrast at all, for one color of light at a time). 

All I claim is that factor _c_ does not depend on the f/no. (which seems self-evident to me)

3) The product of _a x b x c_ therefore has a maximum determined by max(_a x b_) and is scaled overall by _c_. A "perfect" sensor will have c = 1 at all spatial frequencies, and so the MTF is just _a x b_ any lower pixel count sensor (with a smaller value of _c_ independent of f/no.) gives a smaller product at any f/no. (QED)

I believe that anyone who thinks I'm mistaken has to disagree with one of the 3 points (and it would be good to know which), or we have a purely semantic disagreement (most likely due to the 100% viewing when the image gets bigger as the pixels get smaller - that is not the situation I'm describing!).


ps. Seeing another post by Canon-F1. The pixel / Airy disk illustration given by Sean McHugh is *seriously* misleading I know that many many people have been misled by it. Sampling theory tells quite a different story. It is best to calculate using MTF in the spatial frequency domain, as suggested above.

pps. not even neutrinos go faster than light  never mind spaceships.

ppps. there seems to be a bug that prevents me from italicizing one of the "c"s.


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## Gothmoth (Dec 10, 2011)

Denabears said:


> 1) The sharpness, more precisely the MTF, of the system (camera+lens) can be expressed as the product of exactly 3 factors:
> _a_) MTF curve describing lens aberration excluding diffraction,
> _b_) MTF curve diffraction (not quite a simple as the correct formulae kindly given by Canon-F1 would suggest)
> _c_) sensor MTF.



you can forget that argumentation because we already assume a perfect lens. 
again, the LENS has NO influence on the SMALLEST POSSIBLE SIZE of an Airy Disc.

a perfect lens can achive this SMALLEST size, a less then perfect lens can only achive a BIGGER airy disc size.

you canÂ´t do better then the physical minimum.

if you go under this minimum with the size of the photosites you will not resolve more detail.
once you are under this minimum you can make the photosites smaller and smaller but you will not get more details. itÂ´s simply not there.



> All I claim is that factor c does not depend on the f/no. (which seems self-evident to me



and all i say is that at some point the resolution can not be increased by better lens design nor smaller photosites (because of diffraction). 

of course you can resolve more details with smaller photosites when you go to shorter wavelengths. because the size of the airy disc will be smaller with smaller wavelenght.
but that is no real solution for most photographers as we like to photograph visible light not ultraviolett and shorter.


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## Denabears (Dec 10, 2011)

Oh dear, as I feared we are all getting at cross-purposes here, because the assumptions and question are not clear enough (that is even more evident from Gothmoth's perfect lens post that has just popped up).



Canon-F1 said:


> > "In optics, the Airy disk (or Airy disc) and Airy pattern are descriptions of the best focused spot of light that a perfect lens with a circular aperture can make, limited by the diffraction of light.
> >
> > The most important application of this concept is in cameras and telescopes. *Owing to diffraction, the smallest point to which a lens or mirror can focus a beam of light is the size of the Airy disk.* *Even if one were able to make a perfect lens, there is still a limit to the resolution of an image created by this lens.* An optical system in which the resolution is no longer limited by imperfections in the lenses but only by diffraction is said to be diffraction limited."



That's absolutely correct, of course. I did not claim there was no diffraction limit for lenses! - I'm sorry if something I wrote it made you think so. 

My claim is that there is no diffraction limit for *sensors*, so that a higher resolution sensor always gives a better result (however slightly). 

Thanks for the links I am already extremely familiar with them (but you were not to know that). Sean McHugh is not, however, the best source as he ignores sampling theory. 

If you look carefully at my first post you should see that I effectively say that we need 3 blue pixels to resolve the "Airy disk" not just 1. (If you read between the lines and think what produces the 80 lp/mm figure.)

I am being much more subtle than you give me credit for (but that's cool).


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## dirtcastle (Dec 10, 2011)

What about post-processing?

Do increased megapixels give greater ability to process images?

It seems like people are discussing too many variables here.

PLEASE PEOPLE...

Is there an "all other things equal" way to compare different megapixel counts ???

All these formulas and extra variables mean 90% of people viewing this thread probably don't understand the discussion.


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## Gothmoth (Dec 10, 2011)

Denabears said:


> so that a higher resolution sensor always gives a better result (however slightly).



and this is only correct if you can make the wavelength of the rays you collect smaller and smaller.

i repeat again:



> In a digital camera, making the pixels of the image sensor smaller than this would not actually increase image resolution.



the resolution will not get worse when we ignore noise and other effects... but it will be stagnating at some point.


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## Denabears (Dec 10, 2011)

Gothmoth said:


> but that is no real solution for most photographers.



Yes absolutely, perfect lenses are very expensive. That's why I started this whole string of threads off with the 80 lp/mm figure from DXOmark: not theoretical, not nearly the best that can be done, but it still justifies of order 200Mpixels. Diffraction imperfect lens and all.

After all many of us have an 85/1.8 (or an even better lens) and we'd see (a litte) benefit with 200Mpixels at f/5.6.

P.s. another point - compacts with 2 micron pixels are reasonably sharp at f/5.6. That is also about 200Mpixels on full frame (decide yourself).


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## Denabears (Dec 10, 2011)

Gothmoth said:


> Denabears said:
> 
> 
> > so that a higher resolution sensor always gives a better result (however slightly).
> ...


No, the wavelength is of course assumed constant in the 3 point argument. Which step don't you agree with?


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## Denabears (Dec 10, 2011)

dirtcastle said:


> What about post-processing?
> 
> Do increased megapixels give greater ability to process images?
> 
> ...



That's actually a really good point. Extra pixels help preserve high frequency detail that would be lost when transformations are done e.g. to remove lens distortion, level a horizon etc. 

I'm sorry that by my mention of diffraction (which was not even necessary for my argument) I caused the thread to get messy - mea culpa.

Even better: I'll shut up, unless asked a direct question.


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## Gothmoth (Dec 10, 2011)

Denabears said:


> No, the wavelength is of course assumed constant in the 3 point argument. Which step don't you agree with?




ok.. once more before i go to bed. 

my viewpoint is a viewpoint of the physical OPTIMUM.
i donÂ´t care about how good the real lenses are. 
for my argumentation i already have a PERFECT lens (because i talk about the OPTIMUM performance, the best theoretical possible performance). itÂ´s a mathematical view on the best possible resolution.

so with a PERFECT lens i have a MINIMUM size of an Airy Disc.

the amount of detail a sensor will resolve will INCREASE when i make the photosites SMALLER.... UNTIL i reach a point when the photosites are SMALLER then the Airy Discs.

how much smaller is open for argumentation. 
but you will reach that size at some point (btw: that is also why we need other devices then visible light microscopes. because they are limited by the the wavelength of visible light).

so once we have reached that size we can make the photosites on the sensor smaller and smaller but we will NOT resolve MORE detail. at this point you can increase the megapixels (the theroretical sensor resolution) but the output resolution (real information) will be stagnating.

that is because ot the mathematical formula given in the wikipedia article.

the only way you can resolve more details with smaller photosites at this point is when the wavelength of the rays you collect with your sensor will be smaller/shorter (ultraviolett for example).
because a shorter wavelength creates a smaller airy disc with a given aperture.


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## CanonLITA (Dec 10, 2011)

Is one or more of the following correct?

1. even assuming a perfect lens, there will always be a minimum size of the resolvable light information (due to the way light waves behave when they pass through the lens aperture and are forced to change their direction - i.e. difraction) and therefore no more information would be captured be decreasing the size of the pixel below this physical threshold;

2. the minimum useful size of a pixel (as per 1 above) is so small that nowaday we are pretty far from it and it still makes sense (resolution wise, please disregard cost) to squeeze more than 21mp in a FF sensor;

3. even when the minimum useful size of a pixel (as per 1 above) is reached, squeeze more pixels in the sensor still makes sense (resolution wise, please disregard cost) to (a) better post processing, and/or (b) overcome the limits of a real-world-less-than-perfect lens.

Thank you all for your thoughts.


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## Gothmoth (Dec 10, 2011)

CanonLITA said:


> Is one or more of the following correct?
> 
> 1. even assuming a perfect lens, there will always be a minimum size of the resolvable light information (due to the way light waves behave when they pass through the lens aperture and are forced to change their direction - i.e. difraction) and therefore no more information would be captured be decreasing the size of the pixel below this physical threshold



correct and that is why at some point a visible light microscope is not good enough.
the wavelength of the visible light is limiting the size of the structures we can resolve with a visible light microscope. 



> 2. the minimum useful size of a pixel (as per 1 above) is so small that nowaday we are pretty far from it and it still makes sense (resolution wise, please disregard cost) to squeeze more than 21mp in a FF sensor;



in theory yes (if you use big apertures and not f13 and smaller). (*)
but in the real world we have to keep lens imperfections, noise etc. in mind.
so 21MP is not near the limit but with todays technology i question the usefulness of 36MP or even 45MP FF sensors. 

(*) with small apertures you are today limited even with a perfect lens.



> 3. even when the minimum useful size of a pixel (as per 1 above) is reached, squeeze more pixels in the sensor still makes sense (resolution wise, please disregard cost) to (a) better post processing, and/or (b) overcome the limits of a real-world-less-than-perfect lens.



kind of. 
in a perfect world (theoretical world) more photosites would not make things worse.
but we donÂ´t live in a perfect world. 

(a) the size of the files will be bigger -> slower to process in camera and on the PC, more storage space needed. but no real gain on information.

(b) in theory yes. but i doubt that you will see it.
i mean look at the 18MP 7D... crap lenses make no visible better images with that camera.


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## Richard8971 (Dec 11, 2011)

I can't tell you how many times I see guys out shooting who have high $$$, high MP cameras/L glass who can't shoot their way out of a wet paper bag. It is far better to KNOW your equipment, regardless of what EOS body you use and use it frequently!

I have gotten outstanding photos from my XTi through my 7D. My wife still loves her T1i that we bought new 3 years ago and refuses to upgrade to a "pro" body. I only got my 7D because my 40D was damaged beyond repair, not because I needed/wanted a higher MP camera. 

Truth of it is, the higher the MP, the better the glass needs to be to take full advantage of the higher pixel count. Hand shake CAN effect the quality of the photos, regardless of IS or not. Unless you are doing SERIOUS cropping (and if you do, maybe you should buy the lens you really need for the job vs cropping) I really doubt you would ever notice how many MP there were in the PRINTED photo taken from ANY camera. 

Guys, the only time you ever really NOTICE the resolution is when the photo is on your monitor and you are scrolling in to each and every pixel. Take a 8-10MP rebel and take a photo. Take the same photo with a 18MP 7D and have 8x 10's made. I doubt you would ever really be able to tell them apart. The 40D vs 50D was a great example of this. 

I am still a huge believer that good glass & _knowledge_ of your equipment is far superior to high MP camera bodies. If you are buying a new camera, buy the one that you can AFFORD and best suits your needs, regardless of MP size. (IE, 6.5fps 40D vs 8fps 7D, these are very fast cameras and about a grand difference between the two. BOTH produce outstanding images! You do the math.) If you already have a camera, keep it and learn it WELL! Only upgrade if your current camera cannot keep up with your _needs_, not wants. But, of course, if you have plenty of money and a budget isn't of concern to you, none of this really applies. I am mainly speaking to the working folk of the world on this point. If you make your living with photography then I would still say the same. Buy what you can afford and learn it! 

Will any of this stop the MP race? No, and it shouldn't. Cameras will continue to advance and grow in MP. I think however, that more and more people are starting to see that the QUALITY of the photo (regardless of MP size) is far more important than the SIZE of the photo. Right now, the technology is set to do just that and Canon has led the way with the new 1D X by changing people's perception of needing higher and higher MP!


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## Richard8971 (Dec 11, 2011)

I do have to add one point. I would say that the question SHOULD be, not the size of the MP of a sensor but the SIZE OF THE SENSOR!

In other words, FF vs crop sensor. Now, that being said, the original Rebel at 6MP has about the same pixel density of the FF 5D at twice the resolution. Both produce very clean images at similar ISO settings. I'm not talking about cropping, scrolling down to each pixel, blowing up the image... yada, yada, yada. I am simply talking about taking a photo and having a 4 x 6 made!!! I bet you would be hard pressed to tell them apart.

Pixel density has a greater effect on image quality over MP size of the sensor! Unless some breakthrough takes place in CMOS/CCD techology, it will be this way for a long time. 

At this point in camera tech, FF produces smoother photos than a crop sensor with the same resolution at _higher_ ISO settings with similar lenses. Just the way it is...

D


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## dtaylor (Dec 11, 2011)

Gothmoth said:


> but in the real world we have to keep lens imperfections, noise etc. in mind.
> so 21MP is not near the limit but with todays technology i question the usefulness of 36MP or even 45MP FF sensors.



People keep debating the maximum useful FF resolution without considering what we know from APS-C.

The 7D and 5D2 are pretty close in terms of MP (18 and 21). Having a smaller sensor, the 7D is like a crop from a 45 MP FF sensor.

If real world lenses and shooting conditions would render 45 MP of little or no benefit on FF, then they should impact the 7D to the same degree. In other words, even though the 7D and 5D2 are close in terms of MP, their actual performance on resolution charts should be much further apart if the 7D is hobbled by lenses and shooting conditions.

DPReview has tested the resolution of both bodies. They typically stop down to f/8 in these tests. They are:

7D Absolute Extinction (JPEG test)
H 2500 3100
V 2450 3050

5D2 Absolute Extinction (JPEG test)
H 2800 3300
V 2700 3300

Note: I'm using the JPEG test numbers because DPReview didn't do a RAW resolution test on the 5D2. RAW numbers would be a bit higher because ACR is better at resolving fine detail then Canon's JPEG engine / DPP, but the relative difference would remain the same.

The difference in measured resolution is actually a bit less (<12%) then we would expect based on the MP difference (16%). This is real, hard, observed data. If your theory conflicts with it, your theory is wrong, not the real world experience.

The 7D sensor is not limited by the 50mm f/1.4 @ f/8. That's a very good lens at f/8, but it's hardly the only lens that can resolve that much detail, and f/8 is actually just touching on diffraction effects for the 7D's pixel density. This tells us that a 45 MP FF sensor would be quite useful.

How useful? Stitch three 7D frames together overlapped so that you end up with roughly 45 MP. The resulting image will out resolve 6x7 film on an Imacon, and resembles the 645D sample images I've seen in terms of sheer detail and clarity.

Not everyone needs this. Many people would love it. That's why Canon needs a fast shooting/low light FF sensor (1Dx) and a high resolution FF sensor.


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## dtaylor (Dec 11, 2011)

Richard8971 said:


> Guys, the only time you ever really NOTICE the resolution is when the photo is on your monitor and you are scrolling in to each and every pixel. Take a 8-10MP rebel and take a photo. Take the same photo with a 18MP 7D and have 8x 10's made. I doubt you would ever really be able to tell them apart.



I make 16x24" and 20x30" prints. The last two portfolios I made were 17x22. I guarantee you I could tell them apart.


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## Richard8971 (Dec 11, 2011)

dtaylor said:


> Richard8971 said:
> 
> 
> > Guys, the only time you ever really NOTICE the resolution is when the photo is on your monitor and you are scrolling in to each and every pixel. Take a 8-10MP rebel and take a photo. Take the same photo with a 18MP 7D and have 8x 10's made. I doubt you would ever really be able to tell them apart.
> ...



??? The statement I made was regarding 8 x10's, not prints that large. 

And for the record, I have prints in my studio that I have made from my lowly 10MP XTi as large as 16 x 20 that I would put against ANY camera, regardless of MP. Here are a few that I have made large prints from. Mind you, I had to compress them down a tad to allow the 'CR' server to accept them but trust me, there is NO loss of detail or "crispness" in the full size prints! (The ones I posted are jpeg's at 25% compression!)


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## archangelrichard (Dec 11, 2011)

The OP asked a practical question and got an awful lot of impractical answers (a long with a very few practical ones - like Danabears first response)

Look here, folks. FILM is a monstrously higher resolution (anyone who doubts this, try enlarging a sharp film negative to 48 inch x 60 inch - then try doing so with a digital print ... at 1200 dpi for high quality to match the film as close as you can (my printer does 9600 dpi!) and look at the results)

Remember lenses worked to get that sharpness in film; should be able to achieve the same in digital so the lens is NOT the limiting factor; at least not in the way many have stated here (however chromatic aberrations are different for film over digital so that may cause some issues)

So, to the OP; YES what you say is true and it is possible at some point in time that this will happen - but not with today's technology. In medium format you can go with an 80 MP mamiya / Phase One (645 means 60mm x 45mm sensor size); there can be incremental increases in MP count in 35mm format but you are not going to see anything like 80 MP any time soon - that 80mp sensor is a density of 25.6 MP for FF sensors so we know that this is possible easily and we can see the quality of it; above that there are a lot of guesses of 32 - 36 MP's being possible / practical / pending - see all the rumors on this site

NO we are nowhere near the limits of possible technology as many here would like to think; more is definitely possible; but you could be talking of different materials for sensors, etc. to get much higher; Yes for the purpose the OP mentioned, more resolution / more MP is possible and will help in your work as you need to crop (and ignore the insults you have been getting about reframing, etc. from people who failed to read and comprehend the Original post); it just won;t be that soon


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## Richard8971 (Dec 11, 2011)

Sadly, the battle of higher MP and FF vs crop sensor will go on and on as long as Canon, Nikon and others produce different camera bodies with different features.

Is there any one right answer? No. If there was, and I knew it, I would be a very, very, very rich man today. 

The bottom line is, no matter what you know, or think you know, no matter how much money you have or don't have, no matter what camera body you own and no matter what lenses you own or don't is this... Learn the equipment that you DO have and learn it well. If you do... you will be in the position when the time comes to take that ONE perfect photo and make it shine. Be happy and grateful for the equipment that you DO have! That I DO know... 

Photography is fun... continue to make it that way!  

D


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## Richard8971 (Dec 11, 2011)

archangelrichard said:


> The OP asked a practical question and got an awful lot of impractical answers (a long with a very few practical ones - like Danabears first response)



Um, the OP said this... 

"Just because I like to throw fuel on the flame...

There are so many discussions about needing more megapixels with strong proponents on each side, I thought I'd join the fray with some specific examples (especially because it seems like most of the "I need MPs" side is landscape photographers of which I am most definitely not.)

Below I am posting the crop image and then the original. Again, my context is that capturing a decent shot of every athlete in the race is my number one priority. There is little to no time to worry about doing anything artistic, and often even a basic reframing of the shot is more work that I seem to have time for. So some of these are cropped because I think there is artistic value in the a portion of the original image (and 500 shots of "runner...runner...runner...runner" gets old without some creativity ), or as one example shows, simply to isolate the given athlete.

I'm open to contructive criticism if there are things I could do differently to reduce or eliminate my "need" for more MPs (or any other photographic/artistic feedback)."

I would believe that most, if not all of the posts here answer his question. He says he uses the XTi and 40D (both of which I have owned and loved) and wants to know how he can improve on it. Does he need more MP? Hard to say... why? I still believe that glass is more important that camera body. Look, I have seen OUTSTANDING, crisp images taken from a 40D using the 100-400L lens. 10MP guys... great images, just like ones I have taken with my XTi.


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## neuroanatomist (Dec 11, 2011)

Richard8971 said:


> I still believe that glass is more important that camera body.



Bingo. Put a good lens in front of a sensor, and the effects of increasing pixel density will be subtle, at best. Put a crappy lens in front of a sensor, regardless of the pixel density, and the image will be worse.


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## thepancakeman (Dec 12, 2011)

Wow, this thread did not exactly go how/where I'd planned.

There is now another thread on the topic here: http://www.canonrumors.com/forum/index.php/topic,2424.0.html.

I was trying to add a different slant to the MP crowd, as it seems most of them are landscape photographers and their cries for higher MPs is answered with "hey there are a lot of great landscape photos out there that don't have high mps, so what you really need is better ISO or DR performance". There are (or were) a few billboard photographers out there as well, and the response to them was "people shouldn't be looking at your billboard that close anyway." I am attempting to add a 3rd category to the high MP crowd as those of us who "NEED" (?) to be able to do fairly extensive cropping after the fact. I have heard a few fashion photogs jump in in this category as well, and I was just trying to provide some concrete examples (plus maybe solicit some feedback on my images.)

I did get the expected response of: 


Gothmoth said:


> learn composition in camera.



While I'm happy to oblige, I think the challenge is summed up pretty well here: 


Zuuyi said:


> So the OP is supposed to compose 8 different pictures, of different objects, who are moving 10-30/mph(runner vs. biker), in a matter of a few seconds



I think this is an interesting suggestion:


Orangutan said:


> And one more idea: maybe buy a 1DX and use it in video mode. The video resolution might be high enough to let you "sweep" a group and get multiple useable still shots.


Has anyone done or tried that? My one concern would be the time and effort of wading thru the video to ferret out the few that I missed in the stills.

The sample posted by wellfedCanuck is not atypical of race photos. IMHO, the entire photo is fairly weak, and the only 1 of the 7 runners in the photo would likely be interested in purchasing a copy (my principle clients are the athletes themselves.) So if that's the shot I walk away with, I just lost 86% of my potential customers. I think it can be done better.

As a side note relating to neuro's comment--yes distribution does depend on capturing bib numbers, as well as the fact that most runners seem to prefer photos that are framed to include their feet. So between the athletes themselves and the race directors, the full body shots are my "expected" output, the headshots/crops are "bonus" items.

Let me explain my methodology, and perhaps there are other good ideas on how to better accomplish the task (aside from getting a Nikon D800  ). I am nearly always shooting with the 70-200 f2.8 IS. When I have a large group coming, I start at 200 and pan back as the group approaches trying to anticipate where gaps might open up so that I can isolate individual runners. When there's clearly no way to pick them off one by one, I will stop down and try to frame 2 or 3 in focus at the same time (hence the cropping, hence the needing more MPs). Where I am really open to ideas, is how to balance everything: I usually shoot at 2.8 because I need a high shutter speed to freeze the motion. In my (albiet limited) experience, cyclists require a bare minimum of 1/250, with more reliable results starting at 1/800; runners I can get away with 1/125 if there are no other options, but prefer about 1/400. When I stop down it's because I'm going to end up cropping, so then a higher ISO becomes an issue because the noise is more evident in the cropped result.

Of course, maybe a "dude, your crops suck even worse than you originals, so don't bother" would solve the problem too. ???



ferdi said:


> Firstly remember what is expected of you. Practice composition in camera so you don't have to crop in post because this takes forever for a few thousand pictures. If the client wants to publish any pictures he will crop them anyway, and usually not very artistically.
> 
> For your own portfolio, pick a few of the best and edit these more thorougly, including crop, angle, spot removal, vignette, etcetera. 10 MP should still be enough for a web portfolio and smaller prints (up to A4). If not then your upcoming 7D might be the right solution for you; I would have suggested renting it otherwise.



Yup, post processing a few thousand pictures every event does take forever. Yes, I race directors like a few "poster" shots for their websites and advertising, but most of my revenue comes from the individual participants, so the balance is between quality of shots and missing shots. I'm of the mind that a decent shot of nearly every athlete is going to generate more revenue that fabulous shots of a few athletes. But if I can crop some to get those better shots, it's a big plus. However, I'm still very new to this, so if there's a better way to sell/market my photos I am all ears! I've gotten really positive feedback from the few races that I've done, so I think I'm on the right track, but there's always room to do it better, more efficiently, and hopefully more profitably.


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## Orangutan (Dec 12, 2011)

thepancakeman said:


> I think this is an interesting suggestion:
> 
> 
> Orangutan said:
> ...



It don't know if it would work for your workflow, but maybe hire a kid at $10-$15/hr to scan the entire video and enter bib#'s and time slots into a spreadsheet. When someone sends you their bib# and asks, you can look it up in the spreadsheet and go straight to the right timeslots.

You could get some friends to help you test technique and workflow with your current camera. Obviously, image quality will be very different, but it would give you an idea if it's feasible.


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