# Canon may be expensive but...



## dave (Jan 29, 2013)

Their 800mm lens isn't $18000.


http://www.thedigitalpicture.com/News/News-Post.aspx?News=4073


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## charlesa (Jan 29, 2013)

Quite the price, the Canon counterpart is priced better true.


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## dave (Jan 29, 2013)

In fairness they chuck in a teleconverter


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## BrandonKing96 (Jan 29, 2013)

Amazing how the tele-converter on it adds that much :/
Oh well Nikon fanboys can deal with that price while we have the 13,000 USD 800mm!

And I was wondering what the other lens they were announcing would be. I knew the 18-35 was being redone, but the 800 was a surprise.


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## charlesa (Jan 29, 2013)

dave said:


> In fairness they chuck in a teleconverter



No teleconverter is worth that much though!


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## J.R. (Jan 29, 2013)

charlesa said:


> dave said:
> 
> 
> > In fairness they chuck in a teleconverter
> ...



+1 

I just wish Canon would release a 200-400 WITHOUT an in-built TC


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## BM (Jan 29, 2013)

This Nikon new 800mm is interesting thing. On Canon side many bird pros just start replace 800mm to 600mm II.


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## sanj (Jan 29, 2013)

My heart sinks. Canon may price their next 800 to match this...


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## Viggo (Jan 29, 2013)

Well, that is as said, compared to the current Canon 800mm which has been rumored a long time to undergo the same weightreduction as the the other super-teles, then it will most certainly not be 13k anymore..


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## TexPhoto (Jan 29, 2013)

Seriously? Canon people are making fun of a higher price over at Nikon? Somehwere there is a pot calling the kettle black.

How much do you think the Canon 800mm f5.6 IS *II* will cost? $24K?


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## max (Jan 29, 2013)

WWOOOOOWWWWWWW!         
Did you guys see the MTF chart on the Nikon???

Nikon without TC:






Nikon with TC





Borderline perfection!!


Here's the Canon to compare:


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## AprilForever (Jan 29, 2013)

Impressive....


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## raptor3x (Jan 29, 2013)

Dayum


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## RLPhoto (Jan 29, 2013)

#not impressed. :\


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## EYEONE (Jan 29, 2013)

max said:


> WWOOOOOWWWWWWW!
> Did you guys see the MTF chart on the Nikon???
> 
> Nikon without TC:
> ...



You can't compare Canon MTFs to Nikon MTFs. It's not a valid comparision.


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## TexPhoto (Jan 29, 2013)

"Originally trialed and tested under the demanding conditions of the 2012 summer games, the AF-S NIKKOR 800mm f/5.6E FL ED VR maintains...."

Interesting. Did nobody spot one of these because the Canon 200-400-560 were getting all the looks?


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## ChilledXpress (Jan 29, 2013)

max said:


> WWOOOOOWWWWWWW!
> Did you guys see the MTF chart on the Nikon???
> 
> Nikon without TC:
> ...



This must be why no respectable sports/wildlife photographer would ever be caught shooting Canon teles!!! :


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## preppyak (Jan 29, 2013)

BrandonKing96 said:


> And I was wondering what the other lens they were announcing would be. I knew the 18-35 was being redone, but the 800 was a surprise.


Seems like that price point for that lens drives the nail in the coffin of any "update the 17-40" efforts. The going rate of an entry wide-zoom seems to be $750-$850, and I doubt they go cheaper.


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## EYEONE (Jan 29, 2013)

Mikael Risedal said:


> EYEONE said:
> 
> 
> > max said:
> ...



Yes I can.


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## kubelik (Jan 29, 2013)

preppyak said:


> BrandonKing96 said:
> 
> 
> > And I was wondering what the other lens they were announcing would be. I knew the 18-35 was being redone, but the 800 was a surprise.
> ...



I don't know, if Canon can update the 17-40 f/4, and possibly add IS ... it would be wider on the wide end, longer on the long end, a fixed max aperture, and have IS. then they could definitely justify pricing it above this quirky Nikon UW zoom.


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## EYEONE (Jan 29, 2013)

Mikael Risedal said:


> EYEONE said:
> 
> 
> > Mikael Risedal said:
> ...



Hey man, I really don't give a crap. I actually meant that I can come with an "assumption" if I want to.

The way I understand MTFs is that they are not comparable between brands because the the info is not gathered the same way. There are no standards.

If you want links, I have zero desire to find them for you. But I doubt you need them as you seem to be way-super-smart.


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## ishdakuteb (Jan 29, 2013)

max said:


> WWOOOOOWWWWWWW!
> Did you guys see the MTF chart on the Nikon???
> 
> Nikon without TC:
> ...



1. well... do i trust given information from nikon? not really. why? because of this: they claim this image is taken with nikon d5200, but take a look into metadata

sample image 3: http://chsvimg.nikon.com/lineup/dslr/d5200/img/sample01/img_03_l.jpg

update note: recently download the image to ensure the same image that i downloaded before. check metadata and it is now d5200, not d800e anymore, not sure if it is the same image since i do not remember, but it should be the same scene. ONE THING THAT I MIGHT HAVE A GUT TO SAY THAT "NIKON MARKETING TEAM IS ON CANONRUMORS CHANEL "

LOL

2. it is so bummer when comparing old design and old technology to new one. use your brain please



> In Sweden the Nikon 600/4 is almost 5000USD cheaper than Canons 600mm
> Why on earth do you think the street price will be higher on the Nikon 800mm than the Canons?



New design with new technology always much more expensive and this has been proven from time to time right  I guess next Canon 800mm will be about the same price, depending US dollars... will probably not be cheaper than nikon though


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## RLPhoto (Jan 29, 2013)

Mikael Risedal said:


> RLPhoto said:
> 
> 
> > #not impressed. :\
> ...



Profoto is top-notch equipment but Its not what I'll be needing. Love the Modifiers for them.

4x PCB Einsteins are my current plan.


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## preppyak (Jan 29, 2013)

kubelik said:


> I don't know, if Canon can update the 17-40 f/4, and possibly add IS ... it would be wider on the wide end, longer on the long end, a fixed max aperture, and have IS. then they could definitely justify pricing it above this quirky Nikon UW zoom.


Right, my point is more than the cheapest wide-zoom available isnt going to go below $750. Some people, in the wake of the new 24-70 f/4L IS release were saying Canon could make a $4-500 lens, and clearly neither Canon or Nikon are super interested in that.

I also hope Canon wouldn't put IS in a 17-40 lens just to boost the price. For a lens whose primary use is on a tripod, that would be silly


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## kubelik (Jan 29, 2013)

preppyak said:


> I also hope Canon wouldn't put IS in a 17-40 lens just to boost the price. For a lens whose primary use is on a tripod, that would be silly



I hear you there. but their current trend of releases tends to suggest that, if they do update the 17-40, it will most likely have IS built in.

that being said, I'd dispute the fact that the majority of its buyers use it on a tripod. I know lots of people that use the 17-40 specifically as a wide-angle walk-around (or hike-around, rather), and would love to not have to bring their tripod along.


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## garyknrd (Jan 31, 2013)

You will see more of there 800 mm lenses sold I think than the 600 now. That MTF is unreal. Much better than Canon now. But it is rumored that Canon will announce the 800 II soon. I bet that bad boy will be lighter and just as sharp.


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## neuroanatomist (Jan 31, 2013)

Mikael Risedal said:


> MTF tests from Nikon, Canon, Leitz, Zeiss , Hasselblad are real MTF tests and of the lens only



Actually, most of those published MTF curves are not real MTF *tests*, i.e. the manufacturers are not actually _measuring_ the resolution of a _real_ lens. Canon's and Nikon's published MTF curves are theoretical MTFs (as are Sigma's, Tamron's, etc.) - they are calculated curves, generated by a computer algorithm based on the optical design of the lens. AFAIK, Zeiss is the only lens manufacturer that published MTF curves that are empirically measured on a real production lens (not sure about Hasselblad). 

Since neither Canon nor Nikon make public their algorithms for generation of theoretical MTF curves from the lens design, it's not really valid to compare them to one another, nor to Zeiss' real measurements. Comparing _within_ a brand is fine.


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## charlesa (Jan 31, 2013)

Less MTF... more time shooting!


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## sandymandy (Jan 31, 2013)

I think people with a normal income dont even think about getting the highend tele lenses anyway  I just like Canon no matter what Nikon does. Im fine with my gear and so should u!


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## neuroanatomist (Jan 31, 2013)

Mikael Risedal said:


> I have already answer that, go back to page 2, BUT Canon, Leitz , Hasselblad Nikon etc has real MTF equipments and measuring of the lenses , not to be mixed by Photozone and others "MTF" tests .
> There is no problem to measure a Canon lens at Hasselblad MTF lab in Gothenburg and compare that to others



I do not see an answer. Are you saying that the MTF curves published on Canon's (and Nikon's) websites represent real, empirically measured data?


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## neuroanatomist (Feb 1, 2013)

Mikael Risedal said:


> neuroanatomist said:
> 
> 
> > Mikael Risedal said:
> ...



Ahhh...but we _*do*_ know. Canon's published MTF curves are calculated/theoretical, _not_ empirically measured. 

You have two possibly conflicting statements above - "Canon, Leitz , Hasselblad Nikon etc has real MTF equipments and measuring of the lenses," vs. "Canon and Nikon has a predilection to exhibit estimated MTF." Certainly it's possible that Canon has the instrumentation to empirically measure lens MTF (as Zeiss does, for example), and yet chooses to not show those data for their lenses. What is your evidence that Canon has such instrumentation?


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## yogi (Feb 1, 2013)

Here we go again. I have no idea, but Neuro sounds more plausible, as usual. :


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## yogi (Feb 1, 2013)

Meant to say also: good luck Neuro ;D


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## J.R. (Feb 1, 2013)

Popcorn anyone ;D ;D ;D


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## serendipidy (Feb 1, 2013)

Good night everyone. Sleep well and dream of L lenses


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## BrettS (Feb 1, 2013)

Mikael Risedal said:


> J.R. said:
> 
> 
> > Popcorn anyone ;D ;D ;D
> ...



Only a bombastic, arrogant narcissist would say this in a discussion with neuro. Good luck with your charts.


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## neuroanatomist (Feb 1, 2013)

Mikael Risedal said:


> This smells head -room over all, you didn't know how a sensor works, no cameras)



Actually, you were the one in error in the thread to which you're referring, and ultimately, you admitted it. We actually agreed on most points in that thread, though - so if I do not understand how a sensor works, then neither do you. 

Regardless, the point about MTF measurement really isn't worth arguing over. Sleep well...


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## yogi (Feb 1, 2013)

Mikael Risedal said:


> yogi said:
> 
> 
> > Here we go again. I have no idea, but Neuro sounds more plausible, as usual. :
> ...



Here is a fact. I had a bad day at work, and had to work overtime. Think I will quit for the night. Sleep tight and dont let the bedbugs bite.


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## babiesphotos.ca (Feb 1, 2013)

BrettS said:


> Mikael Risedal said:
> 
> 
> > J.R. said:
> ...



Agreed. I've been on this forum less than a month, and I can already see that you don't argue with neuro. I'm glad he spends his time around here...


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## dave (Feb 1, 2013)

I feel bad for starting this thread. It really was only a piece of info! :-[


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## J.R. (Feb 1, 2013)

dave said:


> I feel bad for starting this thread. It really was only a piece of info! :-[



I know exactly how you feel. I started a thread on ISO 50 and you should have seen where THAT ended up ...

http://www.canonrumors.com/forum/index.php?topic=12437.255


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## dave (Feb 1, 2013)

J.R. said:


> dave said:
> 
> 
> > I feel bad for starting this thread. It really was only a piece of info! :-[
> ...



I remember that one. Classic.

That was definitely a time when you would be justified in saying to yourself "it's not me, it's you!"

Hi Mikael, long time no see!


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## dave (Feb 1, 2013)

Mikael Risedal said:


> then read the discussion again.
> and read the suedes answer
> I take it the answer was "yes".
> 
> ...



Excellent, I agree!


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## sanj (Feb 1, 2013)

Wondering why Canon, Nikon would NOT measure actual lenses?


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## rpt (Feb 1, 2013)

sanj said:


> Wondering why would Canon, Nikon would NOT measure actual lenses?


It's a numbers game. If they produce ten thousand lenses of a particular lens (I picked that number out of the air - I could be waaaaaaay out on that one...) and each MTF chart has at least eight squiggles, and each squiggle needs at least fifteen points (with zoom, double that - two charts...) that is a lot of points! So which point do you publish? Best? Worst? Average? Median? Mode? I guess simpler not to publish and statistically QA lenses assuring quality is as expected...


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## neuroanatomist (Feb 1, 2013)

rpt said:


> sanj said:
> 
> 
> > Wondering why would Canon, Nikon would NOT measure actual lenses?
> ...



I wouldn't think so, I don't thing anyone is suggesting that they QC every lens that rolls off the line with a full MTF curve test. However, Zeiss _does_ publish real, empirical MTF curves for their production lenses, whereas Canon and Nikon choose to publish idealized MTF charts. That choice is likely a marketing decision - it makes their lenses look better (but does Zeiss test a whole bunch of lenses, then publish the best curve? Most likely). In the end, it probably does not matter...but I'd prefer to see real data from a real lens, rather than (not-real) ideal data which a real lens may never match.


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## neuroanatomist (Feb 1, 2013)

Mikael Risedal said:


> To all of you , then read the discussion again, and read Neuros answer.



By all means, people should read that thread and observe Mikael '*Half The Photons*' Residal's staunch defense of his explanation that the general mechanism of HTP is that the camera reduces by half the amount of light hitting the sensor, his consistent refusal to admit that his 'explanation' applies only at ISO 100, his avoidance of specific questions from several posters to describe how HTP works at any other ISO setting than 100, etc. Note how here in this thread, he reposts TheSuede's correct description of how HTP works, which matches what others in the thread were saying, but not his own flawed and incorrect explanation. 



Mikael Risedal said:


> The answer is , I have been at Photokina since 30years back as a member of the press every second year and discussed MTF, Lenses,Cameras, scanners with technical chiefs from Nikon, Olympus, Canon , Leica, you name it and I know they have own MTF equipments like Hasselblad



That's all you had to say, Mikael. Why did you feel in necessary instead to lead off by insulting my knowledge and intelligence?



Mikael Risedal said:


> I can tell you people that I have got stringent regulations about my use of	language from CR,



Clearly, there's a reason for that. Those regulations seem to have moderated your overt behavior somewhat (and even that seems to be backsliding), but not your general attitude. Frankly, I find many of your posts to be rude and condescending. I respect your 30 years experience as a photographer, but rather than using your experience and knowledge to help others here on these forums, you choose mainly to comment on Canon's poor sensor performance with regard to DR (you're correct about that, but really, most of us understand it already, so why do you keep beating that dead horse?), argue with people, insult others, and generally make these forums a more hostile place.


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## neuroanatomist (Feb 1, 2013)

Mikael Risedal said:


> Neuro: Do not try to talk away your mistakes and that you dont know its needs a head room to create HTP



Do we really need to go over this again? I have already pointed out _your_ mistake, the incorrect extrapolation of the case of setting the camera to ISO 100 then enabling HTP while in an autoexposure mode (Av/Tv/P), where the camera will then change the exposure by adjusting the shutter speed or aperture one stop, to be a _general_ explanation that the mechanism of HTP is for the camera to adjust the shutter speed or aperture by one stop, when if fact, that only occurs at ISO 100. That's something that TheSuede clearly understood and explained very well, but you still seem unable to grasp.

Of course, headroom is needed to preserve the highlights. We agreed on the 'what' - your error concerned the 'how'. My point was that HTP achieves the additional headroom by exposing at a one-stop lower ISO than is actually selected, *not* by reducing the exposure so that 'half the photons' hit the sensor as you repeatedly stated.

All of that was hashed out to the nth degree in the other thread, there's no point in restating those arguments - if you want to continue to argue your points, please go back to that thread.

As for MTF - read carefully what you wrote:



Mikael Risedal said:


> Page2 I wrote:
> we dont know if this is estimated MTF, Canon and Nikon has a predilection to exhibit estimated MTF results to impress
> 
> and then I wrote:
> MTF tests from Nikon, Canon, Leitz, Zeiss , Hasselblad are real MTF tests and of the lens only



First, you state that Canon shows estimated MTF results. Then you state that Canon's MTF curves are "real MTF tests". Do you understand that your statements conflict with each other? Canon shows MTF plots for their lenses (one for primes, two for zooms) - those data are _either_ calculated/theoretical _or_ they are real/empirical. First you state it's the former (correct) then you state it's the latter (wrong). Your statement about Canon having the equipment to actually measure MTF is irrelevant - fine, they can measure real MTF, but they do not show those data for their lenses, they show only theoretical data. 

It's obvious that we could go around and around about this just like we did with your 'half the photons' argument, and it's equally obvious that there's no point in doing so. You know as well as I that Canon's published MTF curves are theoretical/calculated, and not 'real MTF tests' resulting from actual measurement of real lenses. There is really no point in discussing it further, and therefore, I will not.


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## sanj (Feb 1, 2013)

I felt cheated on learning that Canon publishes hypothetical MFT charts and does not actually test a sample lens.


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## Zv (Feb 1, 2013)

Theoretical is fine by me, I mean theoretically I should be working right now and not reading about MTF charts!


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## neuroanatomist (Feb 1, 2013)

sanj said:


> I felt cheated on learning that Canon publishes hypothetical MFT charts and does not actually test a sample lens.



Maybe. But practically, it probably doesn't matter. How are you going to use those MTF charts? 


If it's to compare one Canon lens to another, e.g. is the 135L sharper than the 28-135?, then the theoretical charts are fine.
If it's to compare a Canon lens to another manufacturer's lens, e.g. is the Canon 24-105L sharper than the Nikon 24-120?, they aren't valid, but that's ok because you can't easily Canon/Nikon lenses on the other manufacturer's bodies, so directly comparing those lenses via MTF curves isn't terribly useful.
If it's to compare your purchased copy of the lens to those MTF curves, unless you have the >$100K equipment to test bare lens resolution, neither theoretical nor empirical MTF data would be useful to you.

In fact, Canon quite likely does test some lenses empirically, as part of the QC process for setting up the manufacturing lines - they just don't publish those data.


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## neuroanatomist (Feb 1, 2013)

Mikael Risedal said:


> Therefore Photodos MTF tests where so valuable (world largest MTF tests collection) (today the magazine "Photo" in Sweden are alone using Hasselblad MTF test equipment [/b]) and to see if a lens have for example been improved or not regarding resolution. The Swedish magazine Foto are also testing new lenses from all manufactures and provide the readers with lens MTF tests



Unfortunately, at least for Photodo, they have MTF measurements for only ~60 of their ~140 listed Canon lenses, and mostly for old ones, just a few of the current lenses have MTF data - e.g., none of the three 24-70mm lenses (but they do have MTF data for the long-discontinued 28-70L), the non-IS 70-200 lenses have data, but none of the three IS versions, etc. But for the lenses that they happen to have tested, it's great that they have published those data! 

As for Foto magazine, I wish I read Swedish. 

Roger's data are definitely useful. 

Reikan FoCal is also now publishing some aggregated sharpness and AF consistency data, but I'm still a bit skeptical about that, since the actual testing is in the hands of many users, not one, which has implicatations for standardization and consistency of results.


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## rpt (Feb 1, 2013)

Good thing tomorrow is Saturday 

We can type all night...

BTW, does anyone need to go to work?


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## Rienzphotoz (Feb 1, 2013)

dave said:


> Their 800mm lens isn't $18000.
> 
> 
> http://www.thedigitalpicture.com/News/News-Post.aspx?News=4073


$18000 is not an issue for me ... coz I can't afford that much ;D ... and I also don't need/want an 800 mm lens.


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## rpt (Feb 1, 2013)

Mikael Risedal said:


> The new Photodo do not show any longer the old MTF tests manage by Lars Klellberg the founder of Photodo, since years back Photodo owns by a UK company


Please start your own threads if you want to argue a point that does not directly apply to the threads you usually write into. Please do not hijack threads of others. Please stay on topic on other's threads. It is simple politeness. We are a community. Please help build it. We ALL share this great forum. Contribute. Life is about sharing. Not about who won an argument!


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## J.R. (Feb 1, 2013)

rpt said:


> Mikael Risedal said:
> 
> 
> > The new Photodo do not show any longer the old MTF tests manage by Lars Klellberg the founder of Photodo, since years back Photodo owns by a UK company
> ...



There was a time when you could log into CR looking for friendly banter but this    ... . It's almost 1:30 am where I am so I beg you ... I've run outta popcorn ... Goodnight!


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## J.R. (Feb 1, 2013)

rpt said:


> Good thing tomorrow is Saturday
> 
> We can type all night...
> 
> BTW, does anyone need to go to work?




My weekend is screwed ... Gotta catch a flight at 10AM and gotta work almost 6 hours straight when I land! Maybe I can get my hands around the camera on Sunday ... OTW I'll be prowling CR over the weekend ... Nite!


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## neuroanatomist (Feb 1, 2013)

rpt said:


> Mikael Risedal said:
> 
> 
> > The new Photodo do not show any longer the old MTF tests manage by Lars Klellberg the founder of Photodo, since years back Photodo owns by a UK company
> ...



I don't see the discussion of MTF curves as being off topic because:

1) The very impressive theoretical MTF curve of the new Nikon 800/5.6 was brought up on the first page, and

2) Once you've said, "Nikon just announced an 800mm f/5.6 VR lens that costs $18,000," really, how much more can you say that's actually 'on topic' besides, "Wow" or "Damn, that's expensive!"?!?


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## J.R. (Feb 1, 2013)

neuroanatomist said:


> rpt said:
> 
> 
> > Mikael Risedal said:
> ...



I understand. But this doesn't have to go so downhill at such a fast pace again...

As usual, you appear to be right whatever Mikael would like us to believe so ... What's the point?


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## yogi (Feb 2, 2013)

J.R, you made me get a strong craving for popcorn last night and i didnt have any! Darn. Will have to get some so the next time i will be prepared.
Has anybody mentioned IQ yet? I would bet that Neuro's IQ is higher than Risedal's. Start a vote thread anyone? Maybe we should ask Marylyn.


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## sanj (Feb 2, 2013)

serendipidy said:


> A wise man realizes that when he finds himself in a place where he is not welcome or doesn't harmoniously fit in, the better part of valor is to excuse himself and leave or to change his behavior. Just saying....



Bit extreme and unfair I think. I for one, like to look at an issue from various perspectives.


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## J.R. (Feb 2, 2013)

Mikael Risedal said:


> *You are quite provocative against me*, with a answer like that, if you understand, your answers had been different
> 
> *JR * *point out one thing there Im wrong*
> 
> ...



I don't for one second doubt your knowledge of cameras. You come up with interesting and good information usually. 

My humble suggestion to you is that you should use the preview button while posting and read carefully what you write so that incorrect / incomplete information is not supplied. My problem with you arose at the time of the "Half The Photons" discussion where, from your posts I got the impression that changing the ISO would somehow change the photons hitting the sensor. I'm sure you knew fully well that changing the ISO does not change the number of photons hitting the sensor then why the charade? What's the point of your expertise if you ultimately end up confusing people - Well you may very well say I'm a noob but there are a number of noobs on CR who log on only to look for some help? 

Every time you have landed up in an argument was because you initially posted something which is incomplete / incorrect and when this was pointed out instead of simply agreeing that you missed out on something, you have adopted the "me against them" approach. Constant posts containing phrases "you don't understand how a sensor works", "poor knowledge", "you have no clue" are in bad taste and are sufficient to get people riled up. 

Not having English as your first language doesn't help matters either. 

BTW, If you are right, there is no need for you to "prove yourself right" - there are sufficient intelligent people here who will agree with you. 

Neuro, Mt Spokane, wickidwombat and the others get a lot of respect here coz they try to help without insulting anyone.


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## J.R. (Feb 2, 2013)

sanj said:


> serendipidy said:
> 
> 
> > A wise man realizes that when he finds himself in a place where he is not welcome or doesn't harmoniously fit in, the better part of valor is to excuse himself and leave or to change his behavior. Just saying....
> ...



I agree. Mikael is knowledgeable and his posts are quite useful. The attitude problems can be sorted out keeping there are cultural issues also - He is, I believe, Swedish and his normal interaction with people may be different from what is considered usual. A word for word translation of a foreign language into English never looks good!


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## rpt (Feb 2, 2013)

Mikael Risedal said:


> J.R. said:
> 
> 
> > Mikael Risedal said:
> ...


Mikael, you just proved J.R. right! Please do yourself a favor and re-read his note and then re-read your response. You keep doing this. You know quite a lot but do not take to time to review your writing. 

You just stated above that that:
*Change TO HIGHER iso means shorter time/f-stop compare to earlier iso, higher iso, GO from 400 to 800 = shorter time or more f-stop =halving the hitting photons* increase amp gain

This does not automatically happen in *M* or *B*! Do you not agree? I agree that your statement would be true for *P*, *Av*, *Tv *and the *Green Rectangle*... Your statement is a generalization. However, it cant be true for all the settings on my 5D3.


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## J.R. (Feb 2, 2013)

rpt said:


> Mikael Risedal said:
> 
> 
> > J.R. said:
> ...



+1. But I'd suggest we kill this debate right here or pray that the admins lock this thread ...


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## rpt (Feb 2, 2013)

J.R. said:


> rpt said:
> 
> 
> > Mikael Risedal said:
> ...


I agree. Motion carried!


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## neuroanatomist (Feb 2, 2013)

Mikael Risedal said:


> *Change TO HIGHER iso means shorter time/f-stop compare to earlier iso, higher iso, GO from 400 to 800 = shorter time or more f-stop =halving the hitting photons* increase amp gain
> 
> * CHOSE Lower the iso means go from 800iso to 400 iso =1 STOP longer exposure time or open up 1 F-stop = let DUBBLE photons hit the sensor = decrease the amp gain
> Changing iso = TIME/F-STOP CONTROL THE numberS of photons TO HIT THE SENSOR
> ...



@J.R. - hopefully I can clarify what Mikael 'Half The Photons' means with the above 'explanation', which I find confusing and incomplete. 

Changing ISO does *NOT* alter the amount of light hitting the sensor. The part he leaves out (and I think it must be intentional obfuscation at this point) is that his statement applies only in an autoexposure mode (P/Av/Tv). For example, if in Av mode you switch from ISO 400 to ISO 800, the camera will then adjust the shutter speed one stop faster to give the same exposure, and it's that change in aperture that results in less light hitting the sensor. If you change ISO in M mode, there is no change in the amount of light hitting the sensor. 

EDIT: I see that rpt has already corrected Mikael's incomplete explanation. @rpt - FYI, the 'explanation' also fails in Av or Tv if at the end of the range, e.g. in Tv mode, switch from ISO 800 to ISO 400, but the lens aperture is already wide open (unless Safety Shift is enabled, then the camera would force a slower shutter speed).


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## sanj (Feb 2, 2013)

serendipidy said:


> sanj said:
> 
> 
> > serendipidy said:
> ...


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## BrettS (Feb 2, 2013)

serendipidy said:


> A wise man realizes that when he finds himself in a place where he is not welcome or doesn't harmoniously fit in, the better part of valor is to excuse himself and leave or to change his behavior. Just saying....



+1

Sorry, I'm not with Team Apologists on this one.

There's no excuse for hostile, insulting language on-line from an adult.


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## BrettS (Feb 2, 2013)

J.R. said:


> Mikael Risedal said:
> 
> 
> > *You are quite provocative against me*, with a answer like that, if you understand, your answers had been different
> ...



This. Exactly.

Excellent summary. Thank you J.R.


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## rpt (Feb 2, 2013)

neuroanatomist said:


> _*<Snip!>*_
> 
> EDIT: I see that rpt has already corrected Mikael's incomplete explanation. @rpt - FYI, the 'explanation' also fails in Av or Tv if at the end of the range, e.g. in Tv mode, switch from ISO 800 to ISO 400, but the lens aperture is already wide open (unless Safety Shift is enabled, then the camera would force a slower shutter speed).


 Yup! You da man!


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## neuroanatomist (Feb 2, 2013)

Mikael Risedal said:


> *are you for real?* then you have to adjust the time/f-stopt to the metering of the subject or you are either over expose or under expose



Ahhh...now I finally understand. Mikael's cameras have infallible metering systems. Snowscapes, fields of yellow flowers, black cats...in all cases, the metered exposure is perfect, so he can always let his camera make exposure decisions for him, so he can use ISO changes to adjust his aperture and shutter speed for him. That must be nice. 



Mikael Risedal said:


> Some of you don't have a clue what discussion is about
> 
> 2. 400 iso the head room is created by two stops , it means halving the hitting light twice to sensor



Indeed. You are stating now that at ISO 400, enabling HTP results in Half The Photons hitting the sensor, making it crystal clear that *YOU* (still) do not have a clue.


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## J.R. (Feb 2, 2013)

Mikael Risedal said:


> Some of you don't have a clue what discussion is about
> 
> 1.HTP at base iso , 100iso underexpose 1 stop = meteringa after 200iso = shorter time/ higher F-stop = halving the read out electrons = create a head room= fill the head room with a gain 100iso = headroom and now a new curve and rooling in the highlight smother.
> 
> 2. 400 iso the head room is created by two stops , it means halving the hitting light twice to sensor= exposing after 400iso but iso gain after 200 iso = new curve and rooling in high lights



The problem that you don't seem to understand is that your posts suggest that by "only" changing the ISO by 1 stop the photons hitting the sensor will be cut in half - something that just isn't correct. 

And please ... Before writing another hurried reply, see my use of the word "only". 

Have a good weekend ... Whatever is left of it!


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## J.R. (Feb 2, 2013)

Mikael Risedal said:


> I thought you had the basic knowledge of time / aperture exposure



I thought the same about you too. Maybe I was wrong

Goodnight!


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## J.R. (Feb 2, 2013)

Mikael Risedal said:


> *This is so fun JR and Neuro are so out in the blue so it will be interesting so se how they shall explain them selt out of this situation
> *



If this is your idea of fun then i can only assume you spread misinformation on purpose.

BTW I don't know whether to laugh or cry at your above post ???


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## J.R. (Feb 2, 2013)

Mikael Risedal said:


> J.R. said:
> 
> 
> > Mikael Risedal said:
> ...



Been there, done that ... It's no use


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## J.R. (Feb 2, 2013)

Mikael Risedal said:


> J.R. said:
> 
> 
> > Mikael Risedal said:
> ...



Thanks ... I don't need your help


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## J.R. (Feb 2, 2013)

Mikael Risedal said:


> J.R. said:
> 
> 
> > Mikael Risedal said:
> ...



As I said before, been there, done that ... It's no use


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## J.R. (Feb 2, 2013)

Mikael Risedal said:


> *I take it once more time
> 1.HTP at base iso , 100iso underexpose 1 stop = meteringa after 200iso = shorter time/ higher F-stop = halving the read out electrons = create a head room= fill the head room with a gain 100iso = headroom and now a new curve and rooling in the highlight smother.
> 
> 2. 400 iso the head room is created by two stops , it means halving the hitting light twice to sensor= exposing after 400iso but iso gain after 200 iso = new curve and rooling in high lights
> ...



As I said before, been there, done that ... It's no use


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## neuroanatomist (Feb 2, 2013)

Mikael Risedal said:


> *no Im saying by exposure after 400 iso you have create a head room by 2 stops compare to 100iso
> what is so difficult to understand Neuro! = exposure after 400 iso = halving the hitting lights twice compare to 100iso*



Hypothetical example: I shoot jpg. I am taking a picture of a forest scene. I am in Av mode, and I set f/8 to obtain the desired DoF, and I chose ISO 400 to get a 1/100 s shutter speed at metered exposure to avoid camera shake, because I foolishly left my tripod at home. Please note, I couldn't care less about what exposure settings would be at ISO 100, 50, or 3200, that's tangential and irrelevant - I choose f/8 and ISO 400 for the reasons I stated. I take a shot, look at the review image, and see blinking highlight alerts where I want detail of the sun-dappled forest floor. I've read that HTP can preserve my highlights. 

If that scenario is confusing, I'll summarize - with HTP off, I set the camera in Av mode, f/8, ISO 400, and the metered exposure gave a 1/100 s shutter speed. 

Answer these questions about what happens when I set HTP to Enable:

1) Does my selected aperture of f/8 change?
2) Does the camera-selected shutter speed of 1/100 s change?
3) Does the amount of light hitting the sensor change?

Please, no hand-waving, no 'please read my earlier posts', no repeating what you've posted before, no referring to what may happen at some other ISO setting that I didn't select and don't care about - just answer those three, simple questions with a yes or a no.


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## J.R. (Feb 2, 2013)

Mikael Risedal said:


> *Yeay yeah no answer, which I could expect from you
> 
> have you noticed one thing, Neuro is quiet, with thoughtfulness , little bit of thinking he probably understands now he is wrong, how about you?
> 
> *



Sometimes no answer is the best answer. I could enter into another debate of "facts" but for what point and purpose? To be at the receiving end of more insults from you? No thank you! 

Please continue living in your la la land of HTP and cutting the photons in half. In the meantime, I'll do something useful.


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## J.R. (Feb 2, 2013)

neuroanatomist said:


> Mikael Risedal said:
> 
> 
> > *no Im saying by exposure after 400 iso you have create a head room by 2 stops compare to 100iso
> ...



You're tough as nails brother ... but I know a lost cause when I see one. All the very best


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## BrettS (Feb 2, 2013)

J.R. said:


> neuroanatomist said:
> 
> 
> > Mikael Risedal said:
> ...



+1 J.R.

The guy's not looking for a discussion, he's only looking to be right.


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## babiesphotos.ca (Feb 2, 2013)

BrettS said:


> J.R. said:
> 
> 
> > neuroanatomist said:
> ...



+1 BrettS


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## neuroanatomist (Feb 2, 2013)

*have you noticed one thing, Mikael is quiet, with thoughtfulness , little bit of thinking he probably understands now he is wrong*


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## J.R. (Feb 2, 2013)

neuroanatomist said:


> *have you noticed one thing, Mikael is quiet, with thoughtfulness , little bit of thinking he probably understands now he is wrong*



Hahaha ... Thanks Neuro ... I may be able to sleep tonight after all ;D

But what's to stop him from making a comeback with the familiar - "you do not understand" / "you have no clue" BS?


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## neuroanatomist (Feb 2, 2013)

J.R. said:


> But what's to stop him from making a comeback with the familiar - "you do not understand" / "you have no clue" BS?



That would indicate to me that he found those three yes/no questions too difficult to answer… :


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## BrettS (Feb 2, 2013)

neuroanatomist said:


> *have you noticed one thing, Mikael is quiet, with thoughtfulness , little bit of thinking he probably understands now he is wrong*



OMFG!

I'll forward you my doctor's bill, Neuro. I think I broke a rib laughing...


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## RMC33 (Feb 2, 2013)

J.R. said:


> Mikael Risedal said:
> 
> 
> > *Yeay yeah no answer, which I could expect from you
> ...



Cutting photons.. OH MY SIDES!


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## RMC33 (Feb 2, 2013)

Mikael Risedal said:


> halving the amount of hitting photons.
> any one still laughing
> 
> *so here ist the questions again
> ...



Still laughing. Don't care.


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## dave (Feb 2, 2013)

Five pages back I was embarrassed for starting this thread, now I'm mortified. 

I'd try and contribute but I honestly don't follow most of it.


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## neuroanatomist (Feb 2, 2013)

Mikael Risedal said:


> neuroanatomist said:
> 
> 
> > Mikael Risedal said:
> ...



Sorry, Mikael - it was a pass/fail test, and you have failed. The answer to all three of those questions is "no". In Av mode, f/8, ISO 400, enabling HTP does not change aperture or shutter speed, and therefore the amount of light hitting the sensor does not change. If anyone believes there a chance Mikael is right, feel free to set Av, f/8, ISO 400 then enable HTP and see if shutter speed or aperture change as a result. 

Back in the other thread, I had come to the conclusion that this was semantics and your inappropriate extrapolation of what happens in the special case of ISO 100 in an autoexposure mode to a general explanation of how HTP works. 

But...the fact that you answered "yes" to the above questions clearly demonstrates that you do not understand how HTP really works. Despite repeated attempts by several people, including TheSuede, to provide an explanation which you could understand, you fail to grasp some details of the concept. At this point, the only logical conclusion is that you are simply incapable of understanding the mechanism of HTP. Not due to language, semantics, etc. - just a fundamental inability to comprehend this concept. You are wrong, you don't get it, and apparently you never will, much less admit that you're wrong and/or incapable of understanding the concepts. 

To paraphrase an earlier statement of yours, it's impossible to discuss this with someone who does not understand the basics - and that someone is you, Mikael. For my part, this discussion is done. Any further statements or questions from you on this matter will be ignored.


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## LetTheRightLensIn (Feb 3, 2013)

dave said:


> Their 800mm lens isn't $18000.
> 
> 
> http://www.thedigitalpicture.com/News/News-Post.aspx?News=4073



And that is why Canon is discontinuing the current one for a Mark II soon....


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## LetTheRightLensIn (Feb 3, 2013)

neuroanatomist said:


> By all means, people should read that thread and observe Mikael '*Half The Photons*' Residal's staunch defense of his explanation that the general mechanism of HTP is that the camera reduces by half the amount of light hitting the sensor, his consistent refusal to admit that his 'explanation' applies only at ISO 100, his avoidance of specific questions from several posters to describe how HTP works at any other ISO setting than 100, etc. Note how here in this thread, he reposts TheSuede's correct description of how HTP works, which matches what others in the thread were saying, but not his own flawed and incorrect explanation.



Doesn't it sort of halve the collected photons though, depending upon how you go about talking about it? If you set ISO400 HTP it uses ISO200 but exposes as if you were using ISO400 so you are shooting ISO200 but as if you were ISO400 so the camera metering does toss away a stop of light compared to what it does when you shoot ISO200 as 200 instead of 200 as ISO400 HTP. So, using the proposed tone curve, it shifts the middle gray and everything else down a full stop so you have 1 stop more room for highlights.

If you compare ISO400 to ISO400 HTP they expose the same way and collect same # of photons but the one without HTP applies one stop more gain than the other and assumes a more typical tone curve will be applied and doesn't shift all of that down 1 stop. But looking at it from the true RAW level ISO400 HTP actual corresponds to ISO200 not ISO400....

It depends how you go about talking about it in detail. I don't know if talk about photon collection is really is the best way. I didn't read that other thread of much of this yet so I don't know went on.

I think it is simplest just to say that:

1. HTP isn't anything special and isn't a real new mode and it is nothing more than software and metering games. 

2. You can do the exact same thing (for RAW shots) by using ISO stop lower in regular mode than what you set in HTP mode and then setting EC -1 to all your shots (or for M mode decide simply use the ISO you want in either case and then for the times you want the 'HTP' shots you decide to set shutter speed one stop faster so as to save one stop more highlights)*. 

3. All HTP is is metering at the labelled stop but applying the gain of one stop less and, in cam (or default in RAW converters), applying a special tone curve that shifts most of the data down one stop and applies different tail and especially top end curves.



*And then you shift things around with the RAW settings to give it a curve a mid-tone point that works (using some built-in profiles you may run into the twisted profiles issue and if you are not skilled at moving sliders and setting TRCs and such it might be a bit trickier with some software to work it out as well than having the software give you automatic starting point under the hood though perhaps, although since most standard starting points and exposures are not fully ETTR you might not actually hit all that must problems at all and might even hit less).





> That's all you had to say, Mikael. Why did you feel in necessary instead to lead off by insulting my knowledge and intelligence?



I'm just guessing, but maybe he was just snapping after all the grief dumped on him in some other threads and stuck in fight fire with fire mode after all of that? Jrista and plenty others certainly insulted him by the bucket load (myself too in some of those threads ;D :'( :'( :'(). Some people who were rather incorrect about a lot of things had been dumping all sorts of insults over a few members for a long time, maybe he just got sick of it and now just snaps back at the slightest hint of anything? Maybe not the best way to go about it, but you can understand a bit where it comes from (plus it is interesting that none of those bashing him now ever got on the cases of everyone who started insulting him and others way back when and they were all fine with it all in that case, why, probably because the ones insulting and bashing in those cases tended to rarely ever treat Canon as anything less than a god.).


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## LetTheRightLensIn (Feb 3, 2013)

neuroanatomist said:


> Of course, headroom is needed to preserve the highlights. We agreed on the 'what' - your error concerned the 'how'. My point was that HTP achieves the additional headroom by exposing at a one-stop lower ISO than is actually selected, *not* by reducing the exposure so that 'half the photons' hit the sensor as you repeatedly stated.



Isn't is basically just semantics?

And from a RAW RAW perspective what is using an ISO as if it were one ISO stop higher but exposing that ISO by one less stop? From that perspective it is collecting half the photons. If we try to do what HTP does ourselves without using it, which we can do because it is not a special mode, then what do we do? We keep using the same ISO we were just using and then make the shutter speed 1 stop quicker = the whole less photos collected scenario. What really is going is a simply a collecting less photons thing.

If you look at from the perspective of does ISO400 HTP collect any less photons (going by autometering) than ISO400, then no it doesn't it is just applying less gain, but then if it is applying less gain it is NOT really ISO400 any more is it so you might say the early way of looking at it is the more natural way?

Both perspectives can be said to be correct but I actually think Mike's seems a bit more the natural way to think about it although I suppose one can argue back and forth about what one considers natural.


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## LetTheRightLensIn (Feb 3, 2013)

sanj said:


> I felt cheated on learning that Canon publishes hypothetical MFT charts and does not actually test a sample lens.



Would you feel any less cheated if your shh copy didn't come close to their best of 50 that they used for the real test though?  ;D

Although it would make f/2.8 vs f/8 performance clearer (since diffraction would be hurting f/8 performance real world) and some designs as I believe Leica once insinuated referring to Canon may be easy enough to make perform in a simulator with every lens carved and placed perfectly and yet an utter bear to produce on a real world manufacturing line where for some tricky designs 99.9% of lenses coming out may have nothing to do with the calculated charts at all. It might make them tune more for real world reasonably consistently produceable designs more??? But they probably do what they do anyway.


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## LetTheRightLensIn (Feb 3, 2013)

J.R. said:


> My problem with you [Michael] arose at the time of the "Half The Photons" discussion where, from your [Michael's] posts I got the impression that changing the ISO would somehow change the photons hitting the sensor. I'm sure you knew fully well that changing the ISO does not change the number of photons hitting the sensor then why the charade? What's the point of your expertise if you ultimately end up confusing people - Well you may very well say I'm a noob but there are a number of noobs on CR who log on only to look for some help?



Because is not just changing the camera back to ISO200. It keeps metering at ISO400 while changing the camera gain to ISO200. And if you meter at ISO400 you are getting less exposure than you would metering at ISO200 which the camera is actually working at. If anything, I think looking at it from his point of view seems less misleading. Effectively it is just an automatic and hidden EC -1 to the shutter speed, that is how you'd replicate it yourself in RAW without using the mode, with an automatic tone curve (applied in cam, and suggested to the RAW converter) making the JPGS and histograms look like EC0 with more highlights instead of a flat EC -1 across the board. How do you replicate ISO400 HTP in say Av mode for RAWs? You shoot ISO200 Av mode with EC -1.


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## LetTheRightLensIn (Feb 3, 2013)

rpt said:


> This does not automatically happen in *M* or *B*! Do you not agree? I agree that your statement would be true for *P*, *Av*, *Tv *and the *Green Rectangle*... Your statement is a generalization. However, it cant be true for all the settings on my 5D3.



But if you shoot a RAW at ISO400 HTP mode at say 1/60th and f/2.8 and looked at the linear RAW file histogram it would look like an ISO200 HTP-off 1/125th and f/2.8 taken image and not an ISO200 HTP-off 1/60th and f/2.8 image.

Or more aptly, if you look at the blinky suggested metering line shown to you in M or B mode it would act just as you say it will for P, Av,Tv,etc.


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## LetTheRightLensIn (Feb 3, 2013)

neuroanatomist said:


> Mikael Risedal said:
> 
> 
> > *no Im saying by exposure after 400 iso you have create a head room by 2 stops compare to 100iso
> ...



1,2,3,
no, no, no

BUT you forget that when you hit the HTP button you are no longer at ISO400 any more but you are at ISO200 only the camera is still metering at as if it were at ISO400. You are not getting to the point of what HTP really is, it is NOT some magic hardware where a new set of photosensors are enabled to capture extra highlights or something, it isn't a 'real' mode, if you want to replicate the mode yourself you can even with a camera that has no HTP button. If you want HTPISO400 and were shooting scenes at say EC0 then you just use ISO200, lock your aperture and then EC -1 or roll up the shutter speed yourself, if in M mode say, 1 stop.

What the camera is actually really doing is just exposing 1 stop less, collecting less photons for any given auto-metering or placement of suggested metering mark.

I can see where your way of looking at it comes from too, but I think it kinda is a less natural perspective.

It doesn't really matter what the camera labels and calls things but what matters in the end is what the sensor is doing, what the shutter speed is, what you get in the RAW file. I think it makes more sense to look at it from if I want to do HTP myself what do I need to do? To get the exact same result I shoot at my selected ISO, keep my selected aperture and then I raise the shutter speed 1 stop faster.


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## rpt (Feb 3, 2013)

LetTheRightLensIn said:


> rpt said:
> 
> 
> > This does not automatically happen in *M* or *B*! Do you not agree? I agree that your statement would be true for *P*, *Av*, *Tv *and the *Green Rectangle*... Your statement is a generalization. However, it cant be true for all the settings on my 5D3.
> ...


I think you need to read that part again. That was not about HTP. That was before HTP sucked up this thread too...


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## neuroanatomist (Feb 3, 2013)

@ LetTheRightLensIn - Changing the ISO has no direct effect on the amount of light that hits the sensor. At ISO 400, enabling HTP does not result in a change in the amount of light hitting the sensor, no difference in the number of photons. Period. What the camera does is apply one stop less gain to the signal generated from those collected photons, then applies a tone curve to the jpg data to boost everything but the highlights back up that one stop. 

Suggesting that at ISO 400, HTP reduces the light hitting the sensor is not just misleading, it's plain wrong. Neither aperture nor shutter speed are changed - and that's a damn good thing because aperture should be selected to give the desired DoF and shutter speed selected to control motion in the image as desired, and the camera shouldn't be changing those parameters if I don't want it to. I disagree with your statement, "_...if I want to do HTP myself what do I need to do? To get the exact same result I shoot at my selected ISO, keep my selected aperture and then I raise the shutter speed 1 stop faster._" What if you wanted motion blur of a fountain, but to preserve the highlights in the scene - would you sacrifice the motion blur you wanted, or stop down and change your DoF or lose sharpness to diffraction? I would do what the camera does with HTP - underexpose by lowering ISO as many stops as needed, and if that took me to ISO 100, it would be time for an ND filter. 

HTP has limitations, foremost being it's limited to one stop of 'highlight recovery'. But if you understand the technical principles behind it, you can overcome those limitations to some extent, while still capturing the desired image in terms of DoF and motion control. 

Like Mikael, you are confusing the actual collection of light by the photon wells of the sensor with what happens to the electronic information into which the energy of those photons is subsequently converted, and with the processing applied to the digitized form of that information even later in the image acquisition process. Those are discrete steps with their own characteristics, and if one is going to discuss the technical details of the image data generation, one should correctly describe and apply those details. You can think of it as a semantic issue if you like, but there was no semantic confusion about providing an incorrect answer to simple yes/no questions - questions which you answered correctly but Mikael did not. 

At the outset, everyone deserves respect, appreciation of cultural and linguistic differences, patience, and the benefit of the doubt. If, over time, someone consistently displays rude and insulting behavior (to the self-admitted point of being placed under strict regulations by the mods), makes no significant effort to contribute in anything but a negative manner, is repetitious and combative, and offers neither apology nor any redeeming characteristics, that person deserves to lose the respect of the community...as Mikael has certainly lost mine.


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## LetTheRightLensIn (Feb 3, 2013)

Mikael Risedal said:


> LetTheRightLensIn said:
> 
> 
> > J.R. said:
> ...



I have to confess that I don't have a clue what you are trying to say here.


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## LetTheRightLensIn (Feb 3, 2013)

Mikael Risedal said:


> LetTheRightLensIn said:
> 
> 
> > neuroanatomist said:
> ...



By you guys are you referring to me too or just the others here???


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## LetTheRightLensIn (Feb 3, 2013)

neuroanatomist said:


> @ LetTheRightLensIn - Changing the ISO has no direct effect on the amount of light that hits the sensor. At ISO 400, enabling HTP does not result in a change in the amount of light hitting the sensor, no difference in the number of photons. Period. What the camera does is apply one stop less gain to the signal generated from those collected photons, then applies a tone curve to the jpg data to boost everything but the highlights back up that one stop.


 

this may be a mess since i typed this out quickly with no thought but:

Yes hitting the HTP button doesn't change the total light now hitting the sensor, but HTP mode both secretly changes the gain 1 stop less AND the metering normally used for that gain by to meter 1 stop down from normal. 

If you want some HTP thing then you have some sort of scene with extra amounts of highlight stuff say a full stop more than typical so you have some gain that manages to let you maintain a high enough shutter speed to stop motion or to handhold. You then go one gain down and that gain is now getting shot letting in 1 stop less light than you'd normally let in for that gain for a scene that had less highlights.

Or you can go tripod and then you do ISO100 and just raise shutter more and more or you add on more and more ND filters and you are saving highlights by exposing the scene to less and less light.

ISO400 HTP EC0 is no longer ISO400 EC0 it is ISO200 EC0 metered to expose (or suggested to be so in M mode meter readings provided) 1 stop less than the camera normally would do at ISO200 EC0, i.e. it is effectively as if you were to shoot ISO200 EC -1.

You are not gaining a stop of highlights at a given gain and keeping the same light coming in, that can't be done of course.

Yeah it is at the face of it just applying 1 stop less gain but normally when you apply 1 stop less gain you'd also let in 1 stop more light too and in this case you are not so you are basically letting in 1 stop less light than you'd normally do for the gain. ISO400 HTP the camera isn't doing ISO400 at all it is doing ISO200 and it decides to do it at EC -1 metering instead of EC 0 metering and because of the latter part you might look at it that is letting in a stop less light. In an M mode scenario where you end up needing in some case to fix both aperture and shutter exactly it might be weird to think of it in terms of letting less light in since in this scenario you always want to let the same light in, but it is still metering in way that is compatible with thinking about it that way. And your scenario below where it adjusts many stops to match your light sounds more like AutoISO button than HTP button to me.


Anyway, you can only save 1 stop more highlights than the prior shot by either now letting 1 stop less light come in at the current gain (set EC -1) or by keeping same light coming in and lowering the gain 1 stop (by either dialing gain down 1 stop and then setting EC -1 or swapping on HTP because that is HTP). HTP lowers the gain one stop BUT to keep the same light coming in it must be set to meter 1 stop less than normal at the new gain that HTP selected under the hood (or simply fail to report the new actual gain being applied). So HTP is metering to let a given gain get 1 stop less light than it would normally be metered for.

So in the sense that it meters 1 stop darker than it normally would for the gain that it is actually using you might say it is letting in one stop less light than normal. If not it would no different than shooting 1 stop lower with normal metering. When you go to replicate it yourself, that is what you'd do set ISO 1 stop lower than what you had it in with HTP and then set EC -1.

If you set your camera to ISO100 EC -1 and then shoot all day in P,Av,Tv you'll get RAWs that can be made to give same results as ones from ISO200 HTP EC0. In M mode you could get files that can be made to deliver the same results using either ISO100 EC -1 as ISO200 HTP EC0 and meterings suggest to you to use would be the same in either case.

It might make more sense to think of ISO200HTP not as any sort of ISO200 at all but as ISO100 and as an ISO100 that gets exposed to 1 stop less light than typical.

You could think of it as exposed to the same light and then has 1 stop less gain applied which it is but since the basis for that decision was based on the meter thinking it had been getting 1 stop more gain....

So you shoot your fountain at f/4.5, 1/15th, ISO200HTP or you shoot it at f/4.5, 1/15th, ISO100 HTP-off and get the same thing, same shutter, same aperture,same SNR,same DR,RAW files are store a touch differently but are basically 1:1.




> Suggesting that at ISO 400, HTP reduces the light hitting the sensor is not just misleading, it's plain wrong.



Yes, swapping ISO400 to ISO400HTP doesn't change the light hitting the sensor. Hit the button and the total light hitting the sensor stays the same.

But saving a stop of highlights for a given amount of sensor gain does mean 1 stop less total light hitting the sensor.

Under the hood, HTP it is doing 1 stop less gain and then setting the metering to expose 1 stop less than normal for that gain. If you have an ISO400 HTP shot and then want to do that on a camera without HTP you would set ISO200 and EC -1. If you shot at ISO400 and EC 0 and wanted to save a stop more of highlights while shooting at ISO 400 what would you do but EC -1 and let 1 stop less total light hit the sensor.

Although it is probably simplest to not talk about getting less photons.




> What if you wanted motion blur of a fountain, but to preserve the highlights in the scene - would you sacrifice the motion blur you wanted, or stop down and change your DoF or lose sharpness to diffraction? I would do what the camera does with HTP - underexpose by lowering ISO as many stops as needed, and if that took me to ISO 100, it would be time for an ND filter.



HTP doesn't lower as many stops as needed. AutoISO does.
HTP just shoots one stop lower and then meters that ISO one stop under.

In this particular scenario of M mode, we are not talking about an at any given gain scenario any more. You just set the gain to balance how much shadows detail you want vs highlights saved. Once you get it ballpark you can then +/- 1 it to save more or less highlights. (although you might want finer tuning than whole stops and might want to tweak aperture or shutter 1/3 of a stop unless you MUST have it left as is exactly).

In the ap AND shutter MUST be exactly locked sub-case of M mode scenario deciding to lower gain a stop might be a bit odd to think of in terms of shooting a given ISO with 1 stop less light coming in since you are in a we decided to keep that fixed scenario, granted so yeah a bit weird. It is still true though that if ISO200 HTP is what ended up working for the particular scenario then so would ISO100 instead and if you cared what the meter told you, then setting that EC -1 same as always though.



> I disagree with your statement, "_...if I want to do HTP myself what do I need to do? To get the exact same result I shoot at my selected ISO, keep my selected aperture and then I raise the shutter speed 1 stop faster._"



It is probably best to just say that shooting HTP at a given gain an EC 0 is 1:1 in RAW to shooting without HTP but at 1 stop less gain and metering set to EC -1. That is normally what I say. Of course in the latter case the histogram and image review may be a bit tougher to judge at first. 

At high ISO where they disallow HTP is would actually make sense to always have it on since the digital gain just lops off the top stop each ISO you go up.


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## neuroanatomist (Feb 3, 2013)

LetTheRightLensIn said:


> Yes hitting the HTP button doesn't change the total light now hitting the sensor



Thank you, you can stop there. I fully understand how HTP works 'under the hood', and how to emulate or 'improve' on it when shooting RAW, as do you - I don't think we need to explain it to each other. My point was that someone who states the opposite of the quoted statement above (repeatedly) is wrong, and does not understand the general mechanism of HTP. Incorrect statements like that can confuse people who are trying to understand the concept, and which is unfortunate and should be corrected.


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## Admin US West (Feb 3, 2013)

Users are now reporting this thread because of the personal accusations. Calling another names is not professional and degrades the forum for everyone.

Please agree to disagree and move on, arguing back and forth solves nothing.


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## sanj (Feb 3, 2013)

Come on!


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## Neutral (Feb 3, 2013)

Was reading this thread and could not help but putting some comments.
Let's look at the root of the discussed HTP issue 
What is the blown highlights means for the sensor? 
Really blown highlights ??
This means that photodiode of the photocell got saturated and any increase in number of captured photons cannot increase current via this photodiode .
Anybody is going to argue about that ?
Then what could be the remedy for this?
Answer is simple - reduce the number of photons.
How this could be done?
Use EC to -1 and then later in processing change gamma in tone curve to raise mid-tones and shadows to the level which would be produced if camera was used with EC=0.
This could be done manually or camera could do that automatically using HTP mode but reporting that all was done with EC=0 , actually cheating camera user.
This all simple physics - anyone could see response curve of the photodiode and understand what it is all about.
It does not matter how you name what is the happening but essence of the process does not change with this.
If photodiode is saturated no further on chip electrical post processing could recover highlights - they already blown.Full stop here. 
This is ABC of electical engineering.


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## neuroanatomist (Feb 3, 2013)

@ Neutral - Thanks, and of course, that's absolutely true if the blown highlights are due to saturation of wells with photons prior to application of the user-selected amount of gain (but note that some gain is applied even at ISO 100, since the 'base ISO' of most current sensors is actually a bit less than 100). 

But highlights can also be blown by less-than-full photon wells being subjected to too much analog gain as they are read out. That can happen at higher ISO settings (which are often needed for action-stopping shutter speeds or narrower apertures chosen for sufficiently deep DoF at handholding shutter speeds). In that case, simply reducing the gain (i.e. ISO) by one stop will preserve one stop of highlights, and that's what HTP does at ISO 400, for example. No change to aperture or shutter speed, so no change in the amount of light hitting the sensor, but rather, a (clandestine) reduction in the analog gain.


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## TheSuede (Feb 3, 2013)

Actually, what Neutral wrote isn't really true.
A well constructed sensor isn't even close to saturating the charge well when the raw ADU reaches maximum, at base ISO. Constructing a sensor that way would mean some serious linearity problems.

The reason why sensors are made to behave like this is that the charge well capacitance behaves like any other capacitance, the potential difference has to be above a certain threshold for the transfer from cell to well to be linear. If you map the ADU/photometric exposure relationship at base ISO you'll see a slowly decaying rate as you approach blown values in the raw file. This rate of decay can tell you how much bigger than the maximum allowed translated digital value the well really is, and it's usually bigger by about a factor of 2.
So no, no modern sensor "blows to white" due to oversaturation in the charge well. The point where that happens is more than 1Ev past blown white in the raw file at the lowest analog gain ISO ("real" base ISO).

The sentence or meaning of "blown white" always relates to the base data you're looking at, no matter what it is. In a jpg, something blown is pegged at 255. In a raw file something blown is pegged at some value close to 15-16,000 depending on ISO and what channel you're looking at. And no, that value isn't 16383 as it "should be" in a 14-bit file, most cameras don't "fill" the raw file - Canon usually use a real raw value range ADU of either 1024-15,000 or 2048-15,000.


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## Neutral (Feb 4, 2013)

@neuroanatomist & @TheSuede :

I think you are both correct but there are two aspects here.
Hopefully modern sensors are designed in a way to prevent photocell saturation in normal conditions and at base ISO saturation point of photocell (or point just below) should match upper level of input voltage range of correspondent ADC. This is required to obtain maximum possible DR from the sensor at base ISO. 

With lower light input (so less input photons) higher digital ISO should increase analog circuit gain so less photocell output should be amplified to the same upper input voltage of ADC.
This also explain why sensor DR is reducing 3db with ISO going up one step (for properly designed up do date modern sensors - e.g. from Sony you see that starting from base ISO). 
So for HTP at ISO higher than base ISO negative exposure compensation could be done just by reducing analog circuit gain.
But at base ISO this might not work - we still would need to reduce number of photons by reducing exposure time or using ND filters to prevent photocell saturation.
Unfortunately there is no freely available information for sensor cell full path gain distribution (from photocell up to ADC) to see actual sensor performance in this respect (for different sensors). This would be interesting to see - actually this is one of the most important parts of the system design.


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## neuroanatomist (Feb 4, 2013)

Neutral said:


> So for HTP at ISO higher than base ISO negative exposure compensation could be done just by reducing analog circuit gain.
> But at base ISO this might not work...



In fact, that is precisely the reason that with the HTP function enabled, the user cannot set the camera to ISO 100 (although technically, that's not really base ISO, which is in the ISO 70-80 range). When HTP is enabled, ISO 200 is the lowest user-selectable ISO, so the camera is able to reduce analog gain by one stop at any user-selected ISO setting (the expansion ISOs where digital gain is applied post-ADC are also unavailable).


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## dlleno (Feb 4, 2013)

If I may make an observation of the way my mind naturally imposes a context to the HTP discussion:

this forum is about Canon cameras and the way they work. With few exceptions the reason people come here is to exchange information about Canon cameras, present and future to be sure. Therefore, when I read the expression "the mechanism of HTP" the primary context is, quite naturally and automatically, "what happens inside my camera when I enable HTP". It means "how are the principles of headroom and ISO gain applied inside my camera". It means "what effect does enabling HTP have on the way my camera behaves".

So with the behavior of Canon Cameras paramount to the discussion, I don't see why it is so difficult to think of Canons implimentation of HTP in these terms: 

Set your Canon camera up to take a picture at ISO 400. 
pause. 
apply cyanoacrylate to the ISO dial -- just not to the electronic gain structure inside the camera  . 
take the picture
pause again. look at the dial. whew it is still set to 400.
enable HTP
look at the ISO dial again. yep, the cyanoacrylate is still there. ISO still set to 400
take another picture. how did the camera behave differently under the influence of the HTP setting?

THAT, to me, is the "mechanism of HTP". Reverting back to the general application of base ISO headroom, the special case of ISO 100, the benefits or characteristics of non-Canon cameras or sensors -- none of that helps describe what Canon cameras do under the vast majority of use cases when HTP is enabled. 

Furthermore, a discussion on the differences between Canon and Sony sensors (and the supporting electronics), as regards their respective behaviors at high levels of light (near saturation) and how to advantage each sensor to the given situation is engaging to be sure ,but doesn't help us understand how Canon Cameras behave differently when HTP is enabled, compared to the way they behave when HTP is not enabled.


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## neuroanatomist (Feb 4, 2013)

charlesa said:


> Quite the price, the Canon counterpart is priced better true.





sanj said:


> My heart sinks. Canon may price their next 800 to match this...



Back to the actual topic of this thread...

If/when Canon releases an updated 800mm 5/f.6L IS, it may very well be in the same price range as the Nikon 800/5.6, if not _higher_. 

Consider the MkII versions of the 500/4 and 600/4 lenses. Look at the selling price of the MkI versions at the time the MkII's were announced, add in the price increase that Canon applied during the long delay between announcement and availability, and you see that the MkII lenses were a 45-50% increase in price. Based on the current 800/5.6 price, that gives a range of *$19-20K* for an 800/5.6 II. 

And don't expect Canon to throw a TC into the deal...


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## wickidwombat (Feb 5, 2013)

neuroanatomist said:


> charlesa said:
> 
> 
> > Quite the price, the Canon counterpart is priced better true.
> ...



I bet higher, and made from titanium and carbon fibre...


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