ISO 1600 vs correcting exposure in photoshop

[iND]

Does anyone have a feel for high ISO 800,1600,3200 on the 50D or 5D image quality vs


lower ISO and correcting the exposure in photoshop.


example.


Shoot ISO 1600 F4 60 vs ISO 400 F4 60 (and try to fix exposure in CS3)

[Chuck Lee]

What your talking about is commonly refered to as "pushing" the exposure in post. I can't speak for the 50D but I can say that I've "pushed" quite a few exposures on images recorded with my 5D.


I would say it is safe to say to use higher ISO and slightly over expose rather than under expose and push in post.


I find my 40D does extremely well at 1600 ISO if I overexpose .3-.5 ev and pull down the overexposure when developing the raw file. By comping up +.3ev I am shooting at a 1250 ISO equivalent. I am loosing 1/3 stop shutter for a given aperture. Or I could just shoot 1250 ISO at 0ev comp. Is there a difference? Not really. I'll splain..........


The 30D & 40D (I have a feeling this goes for the 50D as well) emulate interum ISO values in 1/3 stop increments. Not sure about 1/2, never used it. ( maybe someone could add to this if experienced using 1/2 stop ISO values) When shooting at 160, 320, 640 & 1250 ISO the camera shoots at 200, 400, 800, &1600 but mathematically offsetsthe raw data before writting to the CF card. This is the same as the 1/3 stop of overexposure and results in a much cleaner image than the normal ISO settings. For 125, 250, 500, & 1000 ISO the inverse is true. 100 is pushed mathematically up to 125, 200 to 250 and so forth which introduces more noise into the image. When shooting with the 40D, I use 160, 320, 640, & 1250. If I need to go higher I go to 3200 and over expose by .3-.7 which will give me an eqivalent ISO of 2400 at +.3ev or 2000 at +.7ev (this 2000 is cleaner than 1600 ISO underexposed and pushed in post) Oh, I forgot to mention that there is usually +1ev worth of headroom in a Canon Raw file at 3200 ISO. That is information un reported by the histogram. Simply compensate down during post processing and viola!! normal exposure, withless noise and optimized shutter speed.


The 5D is straight up! I hope the 5D MII is as perfect. 100, 200, 400, 800, 1600, & 3200 are as clean as it gets. Emulated interum values don't offer any benefit from a noise cancelling perspective.


I discovered all this from a post on dpreview a few years ago. I have experimented and shown this to be very true. Here is an excellent study.


http://www.pages.drexel.edu/~par24/rawhistogram/5DTest/5DTest.html ("http://www.pages.drexel.edu/~par24/rawhistogram/5DTest/5DTest.html)


http://www.pages.drexel.edu/~par24/rawhistogram/30DTest.html ("http://www.pages.drexel.edu/~par24/rawhistogram/30DTest.html)This is applicable to the 40D. I'm wondering if anyone can confirm this for the 50D?


Hope this helps,


Chuck

[Daniel Browning]

Does anyone have a feel for high ISO 800,1600,3200 on the 50D or 5D image quality vs lower ISO and correcting the exposure in photoshop.


The short answer is to use the highest ISO you can without blowing important highlights. High ISO reduces noise.

Here's the long answer. ETTR (Expose To The Right) means to increase exposure (f-number, shutter speed, etc.) as much as possible without blowing the highlights you care about. ETTR is the best technique for reducing noise. A single stop of exposure (e.g. f/2.8 instead of f/4) can make more of a difference than 2 stops of ISO (e.g. 400 -> 1600). That doesn't mean ISO is unimportant, just that exposure is more important.

Every camera has different performance at each ISO. The way your 50D and 5D work using "1 stop" ISO settings (not 1/3-stop) is that higher ISO always have less noise than lower ISO until you get to 3200. In other words: ISO 200 has less noise than 100. 400 has less noise than 200. And so on and so forth until you get to 3200. At 3200 and above, the rules change. 3200 has the same noise as 1600. 6400 has the same noise as 1600. 12800 has the same noise as 1600. Therefore, ISO 1600 is the highest ISO that you should use.

The only reason to ever go above 1600 is for convenience: it's necessary for JPEG (if you don't shoot raw), it gives you a brighter review image on the LCD, makes it easier to use autoexposure, flash metering, you don't have to make adjustments in post processing, etc.

But there is a cost associated with high ISO. That cost is clipped highlights. For every doubling of ISO, one stop of highlights are lost. That is why I advise folks to use ITTR: ISO To The Right. That is, increase ISO as much as you can on every shot, without blowing important highlights. But don't go over 1600, as I said above, unless you need the convenience features.

Of course, you often read that high ISO causes noise. The correct meaning of that phrase is this: "At low ISO, I use normal exposures. At high ISO, I use severe underexposure. The underexposure causes a tremendous increase in noise. Increasing the ISO helps to reduce that noise a little, but it's not nearly enough to make up for all the noise caused by underexposure." There is one exception to this: going from ISO 100 to ISO 200 decreases noise so much that it *almost* makes up for the underexposure (it only has about 1/3 stop more noise). That is why ISO 100 and ISO 200 have very similar noise levels.

Hope that helps.

[Daniel Browning]

Great post, Chuck. Thanks for covering the "tweener" (1/3-stop) ISO settings. (FWIW, there are no 1/2 stop ISO settings.)


I would say it is safe to say to use higher ISO and slightly over expose rather than under expose and push inpost.

Agreed.


I'm wondering if anyone can confirm this for the 50D?

I confirm it.

By the way, Chuck, you might be interested to see the chart of dynamic range over ISO settings, made by John Sheehy:

http://forums.dpreview.com/forums/read.asp?forum=1032&message=31378147


The 5D is straight up! I hope the 5D MII is as perfect.

[iND, you can probably ignore the discussion between Chuck and I -- we like to get technical with eachother.]

The read noise ("high ISO noise") is improved greatly in the 5D2, but it still has pattern noise. Canon changed the way tweener ISO are handled in the 5D2. Now they are 30D-style "digital" tweeners instead of analog tweeners like the 5D Mark 1 and 1D series. That's actually a good thing, because the analog tweeners on the 1D series and 5D1 are implemented by a separate gain amplifier that adds enough of its own noise to make it just as noisy as pushing a lower ISO. So to avoid 1/3 stop of clipped highlights, it's better to avoid the tweener ISO on those cameras. (Actually, there is slightly less noise under ISO 400 using the analog tweeners, but often the loss in highlight headroom is not nearly worth it.)

[Oren]

"In other words: ISO 200 has less noise than 100. 400 has less noise than 200. And so on".


Daniel, you'll have to explain more... what the heck?


What ISO does as far as I know, is electronically amplifying the signal - and in such a process you also amplify the noise.

[Daniel Browning]

Let me take another crack at explaining it.



Here is how most people understand high ISO:

When I use autoexposure mode.
At low ISO, the noise is very little.
At high ISO, the noise is very high.
Therefore, high ISO causes noise (incorrect).



The
logical error is that correlation is not causation. In autoexposure
mode, high ISO reduces the exposure. It is the reduced exposure that
causes the noise to be very high. Not the high ISO. In fact, if you had
left ISO the same (low ISO) and just reduced exposure manually, the
noise would be even worse than high ISO. This is because high ISO
actually *reduces* noise. Of course, it doesn't reduce it enough to
make up for the reduced exposure, but every little bit helps.



Here is the correct way to understand high ISO:

When I reduce exposure, it causes more noise.
Sometimes when I reduce exposure, I am left with more highlight headroom than I need.
In those cases, I can trade away the highlight headroom to get less noise by using high ISO.
This
is all thanks to the fact that the 50D sensor technology has an
advanced feature where the actual read noise is reduced at high ISO.
Some other cameras, such as MFDB, don't perform that way.



To prove this to yourself, just take two pictures with the same exposure (i.e. same f-number and
shutter). Set one to ISO 100 and the other to ISO 1600. Then examine
the shadows of both images and tell me which one has more noise. (Of
course there is a difference in blown highlights, which is why I
explained "ETTR then ITTR".)


Decreasing exposure causes an increase in noise. And people tend to
use high ISO at the same time as they decrease exposure, but that
doesn't mean the ISO caused the noise. If it did, then keeping the
exposure the same and increasing ISO would increase noise. It doesn't.
It decreases noise (and blows highlights).



This is one case where the wide use of autoexposure causes many folks to look at things incorrectly.
Saying "high ISO causes noise" is similar to saying "high ISO causes
thin DOF". Everyone knows that's not correct. High ISO *tends* to be
used with wide f-numbers, and wide f-numbers tend to result in thinner
DOF, but that doesn't mean the thin DOF was caused by ISO. In the same
way, noise is not caused by ISO, it is caused by underexposure.



Remember that the least amount of noise results from "ETTR then ITTR." That means to
expose to the right and only then increase ISO (if possible without
blowing important highlights). If someone did the opposite (increase ISO instead of increasing exposure), it would result in far more noise: that would be "ITTR then ETTR", which is the opposite of what I am describing.


Most people have their own home-grown and incorrect
explanations why low ISO has more noise than high ISO when exposure is
fixed. The real reason is that the sensor has physically lower read
noise at higher ISO.



Of course, ideally, we would like low ISO to have the same low read
noise that high ISO has. If it did, there would never be any
reason to use high ISO. A digital push of low ISO would give you the
exact same image as a high ISO shot, but it would have many more stops
of highlight headroom (more dynamic range).



In fact, some cameras are like that, including most MFDB. But the 50D is different. That is why
understanding how high ISO *reduces* noise is important.

[Dumien]

I think I'm falling in love with you Daniel...really...you make me feel brand new (as Simply Red said) hahaha!!


Ok, so, let's say i'm in a weird situation (not so weird to me because it happens all the time) i'm at an ice rink, photographing figure skating. I can stay in only one place, because moving would mean shooting from behing the plexiglass. In front of me there are windows, biiiig windows. The rink is illuminated by lightbulbs on the ceiling (which is pretty far above). I need to stop motion as well as I can.


What I do is get at f/2.8, 1/200-1/320 and ISO 1600. Now, according to you, I'm doing the worst thing possible, cause I'm not really ETTRing because of the need to stop motion, and to get a DECENT exposure I up the ISO to 1600.


In such a situation, what should one do? Maybe this is just the kind of situation you only have to deal with noise, or just get a prime...right?


ANdy

[Daniel Browning]

What I do is get at f/2.8, 1/200-1/320 and ISO 1600. Now, according to you, I'm doing the worst thing possible, cause I'm not really ETTRing because of the need to stop motion,


You are correctly ETTRing. If you shot f/22, that would not be ETTR, because you don't really need the DOF of f/22. But you are doing everything you can do ETTR, so you have done it correctly. Now that you have finished ETTR, the next step is to ITTR. And you already did that. So you are doing "ETTR then ITTR" perfectly.



Maybe this is just the kind of situation you only have to deal with noise, or just get a prime...right?


Right.

[Alan]

What ISO does as far as I know, is electronically amplifying the signal - and in such a process you also amplify the noise.
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That seems right to me, as well.


So, higher ISO is a trade off between lower noise in the shadows, but higher noise in the highlights? Or, is it the other way around?


Either way, isn't it trading one noise for another?

[Dumien]

thanks Daniel, really appreciated... btw, I always shoot M mode because I don't like the camera metering...but that's just me ^^" (i mess up some shots though, but oh well!)


thanks again


Andy

[Daniel Browning]

So, higher ISO is a trade off between lower noise in the shadows, but higher noise in the highlights? Or, is it the other way around?


In the context of fixed exposure (i.e. in Manual mode), it's a trade off between noise and highlight clipping.


For example, take a low light scene with these settings:


1/250, f/8, ISO 100 = 7 stops of highlight headroom (very hard to clip highlights), but lots of noise


1/250, f/8, ISO 1600 = 3 stops of highlight headroom (4 stops are clipped compared to ISO 100), but less noise.

[Dallasphotog]

There is the ever-so-slight chance that some of you guys are too smart.


I was just going to say that when things get on the dark side I push ISO up enough to get shutter speeds I can hand hold and that allow me to freeze the subject motion. From there my motto is "In Photshop I trust."


This is especially true shooting football or baseball at night where the camera is trying to correctly expose areas of the background and I really only care about the subject. I set up manually andlive with underexposed histograms. Usually, a little workwith the shadows and highlights slider in Photoshop curesall.


For weddings, I use RAW files for theversatility provided in Digital Photo Professional. Dark churches never allow an optimum combination of shutter speed, aperture and ISO.


I don't own a 50D or a 5D, but I can say thatI've never had very good images off the 1DMKII above ISO-800 and that the new 5DMKIIseems to produce revenue generating product atISO-12,800; with verynicematerial at ISO-6400. It certainly has the best image quality of the bodies I own or use including the 1DsMKIIIwe use at work.

[Chuck Lee]

iND and Daniel,


We have an excellent post going here. There is alot ofvery interest info to glean here.


It's funny as crap. I thought for all these years that if you changed the exposure increments to 1/2 it would also change the ISO increments to 1/2.... Silly Me.



By the way, Chuck, you might be interested to see the chart of dynamic range over ISO settings, made by John Sheehy


Yeah, Monkey Face Guy.... His Avatar screams "TAKE ME SERIOUSLY" I like his graph...it's nice, but I much more the enjoyed theargument/debate he was having with Gabor. Gabor is very deep like you Daniel. I see over on LL where you guys hit this topic in Jan. Lot's of good stuff there. Thanks.


When photographing, my faculties don't quite reach that deep. I just know what I know from trial and error.


I'm not seeing the headroom in post that Sheehy shows in his 5D MkII graph for the 40D or 5D.


For right nowshooting for reduced noise is more important to me than knowing what my dynamic range headroom is. I find in practice that the 40D when shooting with the ETTR tweenies can post an extra 2ev in highlights whereas the 5D consistently gives an extra1ev across all ISOs. (except 3200). Apparently the 50D and 5D MkIIfollow the 30D and 40D trend.


The 40D tweenies are the same as the 30D so if the new 5D MII is configured the same way 160,320,640 etc. would be the tweenies I'd be shooting with.


On the 5D all the results and opinions I have seen say turn the tweenies off and don't use them. That is correct. I don't.


Question: Has anyone done a dark noise histogram plot of the 5D MkII like the one done here?: Canon EOS 5D Dark Noise Tests ("http://www.pages.drexel.edu/~par24/rawhistogram/5DTest/5DTest.html)


I'm still working with the white balance for RAW "green" histograms and will post some question/results/conclusions when more time is available.


Awesome Guys!

[Jon Ruyle]

Canon changed the way tweener ISO are handled in the 5D2. Now they are 30D-style "digital" tweeners instead of analog tweeners like the 5D Mark 1 and 1D series. That's actually a good thing, because the analog tweeners on the 1D series and 5D1 are implemented by a separate gain amplifier that adds enough of its own noise to make it just as noisy as pushing a lower ISO.


Hmmm. I wonder if they could get even lower read noise by pusing that even further... maybe get rid of iso 200, 800, 3200 and leave only 100, 400, 1600.


As an aside, I believe that read noise always decreases less than linearly. That is, you'll always get lower noise (but lower dynamic range, too) by doing a single low iso exposure than several high iso ones (ie, a single 16 sec iso 100 exposure will have less noise than 16 1 sec iso 1600 exposures averaged out or added together). Does anyone (read: Daniel) know if this is correct?

[Oren]

Ok Daniel, I've just taken 2 pictures both with the same shutter speed and aperture but one with ISO 100 and the other with ISO 1600, but not surprisingly, they look very different - exposure wise, how do you expect me to compare such different pictures?

[Daniel Browning]

Gabor is very deep like you Daniel.


Thanks. That's one of the things I really like about him. (There are some personality quirks of his that aren't as enjoyable, but no amount of faults will make up for the great service he did in building Rawnalyze.)



I'm not seeing the headroom in post that Sheehy shows in his 5D MkII graph for the 40D or 5D.


His chart is just for the green channel. As you know, most light is unbalanced (tungsten, sunset, etc.) so that can make a big difference. It could also be just the way your raw converter is showing things to you. You can eliminate that factor by opening the file in Rawnalyze. That will show you *exactly* where all the values are. (For example, you can drag a square around a card that is supposed to be middle gray, and it will tell you how many stops from *true* clipping it is, such as "-3.5".)



The 40D tweenies are the same as the 30D so if the new 5D MII is configured the same way 160,320,640 etc. would be the tweenies I'd be shooting with.


Yep. They are the same way.



Question: Has anyone done a dark noise histogram plot of the 5D MkII like the one done here?


I did for ISO 1600 and 3200 when I first got it in December, but I can't find them now. I'm sure there are some on the web somewhere. Remind me next week and I'll spend a little time shooting some blackframes. (I was trying to decide if the read noise improvements in ISO 3200 would be enough to sacrifice 1 stop of highlight headroom -- they weren't.)

[Daniel Browning]

Ok Daniel, I've just taken 2 pictures both with the same shutter speed and aperture but one with ISO 100 and the other with ISO 1600, but not surprisingly, they look very different - exposure wise, how do you expect me to compare such different pictures?


With nerdy image analysis tools, of course! Just kidding. Although the noise can be measured directly without adjusting the images, human eyeballs are better at seeing things when they are the same brightness. Just increase the brightness of the ISO 100 shot by +4 EV to match ISO 1600.

(By the way, they have the same "exposure" but different "brightness". The idea that ISO is a part of exposure is a common misconception.)






Hmmm. I wonder if they could get even lower read noise by pusing that even further... maybe get rid of iso 200, 800, 3200 and leave only 100, 400, 1600.


The thing is that all the 1-stop ISO are already performed by only one single amplifier. (Just as all the tweener ISO are performed by one amplifier, making a total of two amplifiers.)

Emil has a chart of the read noises (including tweeners) in his Noise, Dynamic Range and Bit Depth in Digital SLRs ("http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p3.html) essay:

http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/1D3_noisesq_vs_iso-elec.png
http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/DRwindow1d3.png




As an aside, I believe that read noise always decreases less than linearly.


Correct.



That is, you'll always get lower noise (but lower dynamic range, too) by doing a single low iso exposure than several high iso ones (ie, a single 16 sec iso 100 exposure will have less noise than 16 1 sec iso 1600 exposures averaged out or added together).


That's correct. Read noise adds in quadrature, but it still adds.

[Oren]

Yes, I meant exposure as how bright it was of course.


Anyhow, I'm not sure that boosting the brightness is a fair thing to do.

[bob williams]

Wow, This is the conversation I have been waiting for and the explanations "I thought" I needed to better understandexposure and and its realtionship with ISO and noise. Unfortunately,I nowconsider myself at least 3 stops dumber than I was when I started reading this string. Let me see if I have the basics right:


1. High ISO (up to 1600) doesn't cause noise in and of itself--


2. Use of high ISO in the wrong situation can result in noise---


3. If correctly exposed, High ISO results in less noise butcan result in blown highlights--


4. I have erroneously compared high ISO digital to high ASA film -- what was "grainy" in film does not neccesarilymean noise in digital.


Please correct or confirm these assumptions.


Now---the big question----


I normally shoot wildlife, landscape and nature with a 50d and a 100-400L or a 24-105 L (70-200 f2.8L IS is comming). I do prefer shooting within 30 minutes of sunrise or sunset---but many times I find myself in broad daylight and hopefully adjust accordingly. I normally base my settings on desired effect; i.e. Faster shutter for motion control, narrow aperture for DOF etc ---and I set ISO on lowest possible for the shooting situation----What is the error with my method of set-up.


Note--As you have probably already summised, I have discovered that sometimes I get noise when it is unexpected.


Your response is greatly appreciated,





Bob

[Daniel Browning]

You've got it right, Bob!



2. Use of high ISO in the wrong situation can result in noise---


Yes, if the high ISO causes you to reduce exposure, it will result in more noise.



Faster shutter for motion control, narrow aperture for DOF etc ---and I set ISO on lowest possible for the shooting situation----What is the error with my method of set-up.


That's fine, as long as you aren't "wasting" headroom. Low ISO gives you highlight headroom. If you don't need the highlight headroom, the best thing is to increase exposure. If you can't increase exposure, increase ISO. That is the essense of "ETTR then ITTR".

[Chuck Lee]

Daniel,



Emil has a chart of the read noises (including tweeners) in his Noise, Dynamic Range and Bit Depth in Digital SLRs ("http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p3.html) essay:



Looks like the link is dead.


Do you havea copy you could post?


Thanks,


Chuck


P.S. Madison quit cause I called him a tool. I feel really bad. I was just jok'n around. He's European. woops.

[bob williams]

Thanks, that is very helpful. I appreciate the feedback Dan.





Bob

[Daniel Browning]

Looks like the link is dead.


Do you havea copy you could post?





Here ya go:


http://thebrownings.name/images/sensor/2009-07-29-iso-dr/1D3_noisesq_vs_iso-elec.png


http://thebrownings.name/images/sensor/2009-07-29-iso-dr/DRwindow1d3.png

[Chuck Lee]

Thanks

[Johnny Rasmussen]

Very interesting topic and I totally agree. Take a look at this Norwegian site where you can see examples. I have run it through google translate so I hope the link is working.


Testing 50D and exposure:


http://translate.google.com/translate?prev=hp&amp;hl=no&amp;js=y&amp;u=http%3A%2F%2Fwww.fo to.no%2Fcgi-bin%2Farticles%2FarticleView.cgi%3FarticleId%3D412 81&amp;sl=no&amp;tl=en&amp;history_state0=





Testing D90 and exposure. This example shows that ISO 6400 + 1.3EV can look as good as ISO 1600 if the exposure is right:


http://translate.google.com/translate?prev=hp&amp;hl=no&amp;js=y&amp;u=http%3A%2F%2Fwww.fo to.no%2Fcgi-bin%2Farticles%2FarticleView.cgi%3FarticleId%3D413 16&amp;sl=no&amp;tl=en&amp;history_state0=





PS! I dont know how to make a hyperlink. Copy and paste and look at Exposure and ISO properties.








Johnny

[Chuck Lee]

Jonny,


Thanks for the links. To add a hyperlink to anything just select those words and click on the little chain icon (4 left of the happy face) and paste the url in the appropriate box. Just remember the "http://" has to be in front of the "www"


Like this: Canon Rumors ("http://www.canonrumors.com/)


Voila, as the French say

[Dumien]

First, I'm very impressed with google translation, it's pretty darn accurate, isn't it?


As for the pictures: TOTALLY AWESOME...see, I tried to do a little test with my XSi, but I guess that i'm going to see better results when I'll take pictures in real life...


thanks Johnny...(btw, that's my nickname! Everybody calls me johnny at school..well, used to: i'm finally done with highschool hahaha)


Andy

[peety3]

(By the way, they have the same "exposure" but different "brightness". The idea that ISO is a part of exposure is a common misconception.)



In a purely digital world, you may be right. In the days of film, f/4 and 1/500th might underexpose some film and overexpose other film. Otherwise, Bryan Peterson must be wrong in calling it the Exposure Triangle...and he's certainly sold a lot of books calling it that.

[peety3]

The short answer is to use the highest ISO you can without blowing important highlights. High ISO reduces noise.

Here's the long answer. ETTR (Expose To The Right) means to increase exposure (f-number, shutter speed, etc.) as much as possible without blowing the highlights you care about. ETTR is the best technique for reducing noise. A single stop of exposure (e.g. f/2.8 instead of f/4) can make more of a difference than 2 stops of ISO (e.g. 400 -&gt; 1600). That doesn't mean ISO is unimportant, just that exposure is more important.

But there is a cost associated with high ISO. That cost is clipped highlights. For every doubling of ISO, one stop of highlights are lost. That is why I advise folks to use ITTR: ISO To The Right. That is, increase ISO as much as you can on every shot, without blowing important highlights. But don't go over 1600, as I said above, unless you need the convenience features.





This took me a long while to digest and interpret. What I finally figured out is that you're suggesting that we shoot in manual mode, starting at ISO 100 "for every shot", and choose "exposure" (using your definition of exposure) values such that the desired image is (hopefully) captured while also maximizing the light upon the sensor, without so much light that important highlights are lost. If it's impossible to achieve the desired image via aperture and shutter values (i.e. slowing the shutter will result in a blurry image, or opening the aperture will thin the DoF too much), it's best to increase the ISO to maximize the light upon the sensor, without so much light that important highlights are lost.


My translation of all of that is that it's best to achieve a right-justified histogram (using appropriate margins for the details we wish to keep) by prioritizing the widest artistically-reasonable aperture and the slowest artistically-reasonable shutter, and then the minimum amount of ISO increase. My initial interpretation was that I should set my camera to ISO 1600 and lock that in, which I don't think is the desired interpretation.

[Daniel Browning]

In a purely digital world, you may be right. In the days of film, f/4 and 1/500th might underexpose some film and overexpose other film. Otherwise, Bryan Peterson must be wrong in calling it the Exposure Triangle...and he's certainly sold a lot of books calling it that.


There's nothing wrong with calling it the Exposure Triangle: that does not imply that changing ISO (without changing f-number or shutter speed) is changing exposure. I do not recall Bryan Peterson ever using the incorrect definition of exposure in "Understanding Exposure".



This took me a long while to digest and interpret. What I finally figured out is that you're suggesting that we shoot in manual mode,


I did use manual for illustration, but it's possible to use the "ETTR then ITTR" technique with autoexposure as well.


starting at ISO 100 "for every shot", and choose "exposure" (using your definition of exposure) values such that the desired image is (hopefully) captured while also maximizing the light upon the sensor, without so much light that important highlights are lost. If it's impossible to achieve the desired image via aperture and shutter values (i.e. slowing the shutter will result in a blurry image, or opening the aperture will thin the DoF too much),


Yep.



it's best to increase the ISO to maximize the light upon the sensor, without so much light that important highlights are lost.


Increasing ISO doesn't change the light on the sensor at all. It increases brightness and decreases read noise.



My translation of all of that is that it's best to achieve a right-justified histogram (using appropriate margins for the details we wish to keep) by prioritizing the widest artistically-reasonable aperture and the slowest artistically-reasonable shutter, and then the minimum amount of ISO increase.


That will result in the same settings (Tv/Av/ISO) that I am suggesting.



My initial interpretation was that I should set my camera to ISO 1600 and lock that in, which I don't think is the desired interpretation.


Correct. ISO 1600 always has less noise for a fixed exposure, but that doesn't mean we should always use it. High ISO has a price: clipped highlights. That price is always far too high to pay, except when we are in low light, and we no longer need the normal amount of highlight headroom.

[dmckinny]

My initial interpretation was that I should set my camera to ISO 1600 and lock that in, which I don't think is the desired interpretation.


Correct. ISO 1600 always has less noise for a fixed exposure, but that doesn't mean we should always use it. High ISO has a price: clipped highlights. That price is always far too high to pay, except when we are in low light, and we no longer need the normal amount of highlight headroom.






OK now, the lights are starting to turn on for me. Daniel, I think I was not comprehending what you meant by 'highlight headroom'. Would the following statement be correct?


Highlight headroom is roughly analogous to available dynamic range. In the case of a low light shot, we slow the shutter as much as is acceptable, and open the aperture as much as is acceptable. Then when there is still not enough light for our needs, we increase the ISO. The trade off here is that by increasing the ISO we are sacrificing dynamic range (losing highlight headroom), in order to decrease read noise and (in the case of digital) amplify the signal on the sensor. This works in low light because there is less dynamic range in the scene, so we can use the higher ISO.

[Daniel Browning]

Would the following statement be correct?


Highlight headroom is roughly analogous to available dynamic range. In the case of a low light shot, we slow the shutter as much as is acceptable, and open the aperture as much as is acceptable. Then when there is still not enough light for our needs, we increase the ISO. The trade off here is that by increasing the ISO we are sacrificing dynamic range (losing highlight headroom), in order to decrease read noise and (in the case of digital) amplify the signal on the sensor.





All correct.



This works in low light because there is less dynamic range in the scene, so we can use the higher ISO.


I would put it differently. Low light scenes tend to have very high dynamic range, and we'd love to shoot them at ISO 100 if we could. It's just that reducing the noise is *so* important that we will sacrifice the headroom to get it. That is, we'll go from 7 stops of highlight headroom down to 3 stops, but the decrease in noise will be well worth it.

[canoli]

wow, interesting discussion.


What I got from this thread is basically this: make sure you ETTR and all will be well, regardless of how you get there - wider aperture, longer exposure, higher ISO. When creative intent dictates you use a small aperture, increase your exposure. If you can't handhold because the required exposure is too long, work off a tripod. No tripod? Increase ISO. The goal is ETTR no matter what. Yes?


The benefits of ETTR, the way I understand it, is you'll be getting the most noise-free images and you won't give up anything that can't be "fixed" in post. Example, a dark scene, ETTR, ends up looking way too bright on your LCD. But if you want to reproduce the scene accurately in your print, you'll have all the latitude you need to recreate that dark scene. If on the other hand you tried to shoot it "correctly" you'd have very little HL detail and a world of noise in the shadows.


Is that all true?


I hope so, because I've been shooting that way for a year now, ever since I learned about the linear capture of digital sensors...

[Daniel Browning]

Thanks for the response, Canoli. I'll try to clarify and be as helpful as I can.



What I got from this thread is basically this:


Your post is close enough. You are using the optimal technique, and that's really all that matters in the real world.


The only nits I would pick are in the vocabulary and the reason "why" you use that technique. You can stop reading now if you're not really interested in the "trivia" of knowing why your technique is better, or what the correct vocabulary is.



make sure you ETTR and all will be well, regardless of how you get there - wider aperture, longer exposure, higher ISO


First of all, ISO is not a part of "Exposure", and therefore it is not a part of ETTR. Exposure does not include "ISO" because it is a word that only relates to the total amount of light the falls on the sensor per area. I realize that many photographers think that "Exposure" means "brightness" and that increasing ISO increases "exposure", but that's not correct. The correct definition is given, for example, in the book "Photography", Eighth Edition, by London &amp; Upton. It is:
<p style="padding-left: 30px;"] Exposure = Intensity (aperture) x Time (shutter speed)


As for "regardless of how you get there" -- I wouldn't put it that way. Because it's very important that exposure be increased before ISO. If you increase ISO when you could have increased exposure, you will get far more noise. In other words, "ETTR then ITTR". Don't "ITTR then ETTR". I'm sure that this is precisely what you meant, but I thought I would point it out for the reader just to make sure there's no confusion.



If on the other hand you tried to shoot it "correctly" you'd have very little HL detail and a world of noise in the shadows.


Actually, shooting it "correctly" (not ETTR) gives you *more* highlight detail. ETTR (and ITTR) gives you less noise in the shadows at the cost of highlights (nothing for free). So you would only do it if you had nothing important in the highlights or the shadows were just so important that it doesn't matter what's in the highlights.



I hope so, because I've been shooting that way for a year now, ever since I learned about the linear capture of digital sensors...


The value of ETTR has nothing to do with the linear capture of sensors. That was a myth made popular by a Luminous Landscape article, where they said that it results in more levels being used (2048 levels in the first stop, then 1024, etc.). That's totally wrong and has no benefit whatsoever because of photon shot noise.


The real reason why ETTR has so much value is because it results in *more light*. More light means less photon shot noise and more distance between any given tone and the read noise of the sensor. I hope that helps.


Kind regards,

[Jon Ruyle]

What I got from this thread is basically this: make sure you ETTR and all will be well, regardless of how you get there - wider aperture, longer exposure, higher ISO.


No. It is true that with a *given exposure* you want the highest iso possible without clipping highlights (high iso means lower read noise). But you always get less noise with a longer exposure and lower iso than with fast exposure and high iso, because the more light you let in the less photon noise you will have. So Daniel is *not* saying we should shoot iso 1600 1/1600 sec instead of iso 100 1/100 sec (at least I don't *think* he is- correct me if I'm wrong, Daniel). He is saying that with a *given* shutter speed and a *given* aperture, we want the highest iso possible without clipping highlights.


Using a low iso and low shutter speed is probably more important in most cases, because photon noise usually dominates read noise. This is why I *wish* auto iso worked in the reasonable way (ie, user chooses shutter speed and aperture and camera exposes correctly). If I take a picture in which the shutter speed is four times what it has to be, I've lost 75% of the light I could have had. This is a big deal when you consider how much we pay for fast lenses and sensitive ccd's.

[Jon Ruyle]

Oops-- once again Daniel beat me to it [:)]

[canoli]

Thanks Daniel - I think (!).







If on the other hand you tried to shoot it "correctly" you'd have very little HL detail and a world of noise in the shadows.


Actually, shooting it "correctly" (not ETTR) gives you *more* highlight detail.





Here you're referring to the amount of light hitting the sensor but not the end result, right? I should've said "you'd have very little HL detail..." when you bring it into post and attempt to recover the HLs. You end up with very little HL detail because in post you'd have to boost the shadows so much (to see the HLs) that
the result would be hopelessly noisy. That's what I meant by shooting it "correctly" and getting it wrong. (crossing fingers) Have I got it?



ETTR (and ITTR) gives you less noise in
the shadows at the cost of highlights (nothing for free).


But only if you blow out the HLs, no? The "cost of highlights" is only payable to HLs you care about, naturally. Higher ISO by default doesn't cost you HL detail does it?


I'm guessing "read noise" and "photon shot noise" - if it's not the same as Luminance and Color noise - is a mathematical discussion that's over my head. Maybe the whole discussion is. But thank you for indulging me and for the boost of confidence, telling me that I'm "using the optimal technique," even if I can't talk about it or understand it very well.


So I can safely ETTR all the time (aperture/shutter speed, then ISO) and I'll be using my camera to its fullest potential, capturing the widest possible dynamic range. As long as that's true I'm good to go!


Thanks again Daniel.

[Daniel Browning]

You end up with very little HL detail because in post you'd have to boost the shadows so much (to see the HLs) that
the result would be hopelessly noisy. That's what I meant by shooting it "correctly" and getting it wrong. (crossing fingers) Have I got it?


Close enough for me. [:)] Personally, I find that the highlights are never noisy enough to be a problem (even in a severely underexposed shot). It's noise in the midtones and shadows that bothers me.






But only if you blow out the HLs, no? The "cost of highlights" is only payable to HLs you care about, naturally.


I agree.






Higher ISO by default doesn't cost you HL detail does it?





It does if you think of it this way:


f/2.8 ISO 400: 3 stops of highlight headroom


f/4 ISO 400: 4 stops of highlight headroom, but now 1 stop of "footroom" has been lost to noisy shadows.


f/4 ISO 800: 3 stops of highlight headroom, back to the same 3 stops of headroom as the first shot.


f/4 ISO 1600: 2 stops of highlight headroom, but now those shadows are far less noisy and are more usable.



I'm guessing "read noise" and "photon shot noise" - if it's not the same as Luminance and Color noise - is a mathematical discussion that's over my head.


It's not the same as luminance and color noise, but it's not over your head, either. Think of it as "read noise = shadow noise" and "photon shot noise = midtone and highlight noise".



So I can safely ETTR all the time (aperture/shutter speed, then ISO) and I'll be using my camera to its fullest potential, capturing the widest possible dynamic range. As long as that's true I'm good to go!


You're doing great!

[Johnny Rasmussen]

Hi, Andy (Johnny)[:)] !


I&acute;m glad you liked the article. You are right, Google translated it very accurate.


My nickname at highschool was Johnny Cash btw, deep voice and a guitar. :-)





Johnny

[canoli]

Ah...thank you again Daniel! You're a heckuva teacher, and as long as I'm not imposing, I'd love to continue the discussion. (If you'd rather not get into it, I understand. I know sometimes teaching can be tedious...)


The part that baffles me is this:










Higher ISO by default doesn't cost you HL detail does it?





It does if you think of it this way:


f/2.8 ISO 400: 3 stops of highlight headroom


f/4 ISO 400: 4 stops of highlight headroom, but now 1 stop of "footroom" has been lost to noisy shadows.


f/4 ISO 800: 3 stops of highlight headroom, back to the same 3 stops of headroom as the first shot.


f/4 ISO 1600: 2 stops of highlight headroom, but now those shadows are far less noisy and are more usable.





Where do these statements come from? Are they arbitrary figures, just so you can illustrate the differences? Or is "f/2.8 ISO 400: 3 stops..." (and the others) simply true, all by itself?


Aren't headroom values dependent upon the dynamic range, which obviously vary from scene to scene? Or are these statements "constants" in some way?


Sorry if I'm complicating this. I always think of Headroom as a safety margin of sorts, a tonal range that is available in the development process, existing only because the photographer didn't clip the HLs. How much headroom is a function of the exposure (and the scene's avail range of course) and then the process in PP (the creative intent).


But even if I'm correct in thinking of headroom this way, I don't see how "f/4 ISO 400: 4 stops..." (or any of them) is automatically true.


I mean, I see the trend - higher ISOs squeezing the HL headroom - but how or why does it happen?


Again, sorry if I'm complicating this. The answer may very well be staring me in the face but I don't see it yet.


If you feel like continuing, I would really appreciate reading more of your thoughts on this subject.


Thank you very much!

[Daniel Browning]

Where do these statements come from?


3 stops was chosen because that's a typical amount of headroom for the autoexposure system to meter for.






Are they arbitrary figures, just so you can illustrate the differences? Or is "f/2.8 ISO 400: 3 stops..." (and the others) simply true, all by itself?


It's arbitrary in the sense that I chose the number that Canon uses for its AE system. But raw photographers are free to choose any amount of headroom they need for the shot, from 1 stop to 7 stops. The AE system will tend to choose between 3 and 4.5 stops, depending on the camera, settings, and other factors.


What's not arbitrary is the *relative* amount of headroom. When exposure is reduced by a stop, without changing ISO, headroom increases exactly 1 stop, every time. In a fixed exposure, ISO 800 always has 1 stop less headroom than ISO 400. That's why it went down from 4 to 3 in my example. But if I had chosen a different headroom to start with, say 5 stops, then it would have gone from 5 to 4.



Aren't headroom values dependent upon the dynamic range, which obviously vary from scene to scene? Or are these statements "constants" in some way?


You've got it. Headroom is chosen by the photographer based on the scene. A black lab against a black wall holding a black ball will need far less headroom than a white dress in sunlight against a black wall.



Sorry if I'm complicating this. I always think of Headroom as a safety margin of sorts, a tonal range that is available in the development process, existing only because the photographer didn't clip the HLs. How much headroom is a function of the exposure (and the scene's avail range of course) and then the process in PP (the creative intent).


I don't think that's the best view of headroom. I'll try to explain. The camera just captures linear values from clipped to noise. It knows that 1 stop less light means it is "darker". But it has no concept of "black". Black is just the point where we, as humans, say "this is too noisy, I'm going to call it black."


Raw files have no concept of "middle gray", either. Middle gray is just the point where humans say "make *this* certain brightness into the midtone". That could be 7 stops below clipping, which would result in a *lot* of highlight headroom. Or it could be 1 stop below clipping, which would result in very little highlight headroom. Cameras tend to meter for 2.5-4.5 stops of highlight headroom, and most raw converters are tuned for this as well. It can be quite difficult to get raw converters to use a different value. Film had 6 stops of highlight headroom.



I mean, I see the trend - higher ISOs squeezing the HL headroom - but how or why does it happen?


I don't know exactly what goes on inside the camera. I just know that it clips it. :)

[canoli]

This conversation is really revealing my limits of understanding - of the entire digital capture universe, and it's also extremely helpful.


Thank you!


So headroom really isn't some fluctuating range of tones, dependent upon the scene. It's really best defined as what the recording medium is capable of. Is that the right way to think of it? And so Canon can choose to make f/2.8 have 3 stops at ISO 400, or it could've chosen something different. The way it is, with RAW converters tuned similarly, is no accident...


On a related note - does any of this discussion apply to shooting on a tripod? I always use ISO 100 on a tripod. But there's that "long-exp. NR" Function setting, so I'm wondering when that comes into play...


I've read the manual of course. I also bought the Canon EOS 40D Guide to Digital SLR Photography by David D. Busch - and not to knock either one of them too harshly, but there is a lot of misinformation out there. Mr. Busch's book says, "Another way of adjusting exposure is by changing the ISO sensitivity..." and so on.


He describes the long-exp noise reduction as dark frame subtraction - I guess like what HotPixels Eliminator is supposed to do.


http://www.mediachance.com/digicam/hotpixels.htm ("http://www.mediachance.com/digicam/hotpixels.htm)


I've never used the long-exp. NR on my 40D. Do you think it's worthwhile using it? According to David Busch's book it's good for shutter speeds slower than 1 second, although you'll trade off some detail if you use it.


I don't know, I took a 30-sec shot the other night - was trying to open up shadows, and also see if the resulting image was full of noise and it really wasn't, it was okay. I was at ISO 100 and f/16. I still didn't light up the shadows the way I'd hoped to, but close enough. Eventually it'll be part of a composite. Here's a 100% crop from the upper RH side, out of ACR to convert to .jpg, nothing else changed.


Would I have done better with a higher ISO and a faster shutter speed?


(and at the risk of being redundant and appearing ridiculously obsequious, THANK YOU for all your help Daniel! [:$])


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[Jon Ruyle]

I've never used the long-exp. NR on my 40D. Do you think it's worthwhile using it? According to David Busch's book it's good for shutter speeds slower than 1 second, although you'll trade off some detail if you use it.


That may be an okay rule-of-thumb, but thermal noise depends on a lot of factors other than shutter speed. It is much worse at higher temperatures (which is why the serious long exposure guys cool their cameras), and like all noise, is most noticeable when the signal is weak. I think your picture looks fine and does not need long exposure NR.


If you took a 5 minute or longer exposure of the night sky, thermal noise would be obvious. I find that in these cases, the camera's built-in long exposure NR works very well.

[canoli]

ah, gotcha, thans Jon. So then it's strictly thermal noise that the long-exp. NR function addresses? And it can be mitigated by not using Live View I'd guess, also, shooting in lower ambient temps...


(Just how many types of noise are there with digital sensors?)


So with a tripod, is there ever a reason to boost ISO beyond 100, short of long (5-min.) exposures? (or even then?)


Although come to think of it, even at ISO 1600, what was a 5-min. exposure at ISO 100 is still going to be pretty long...something like...let's see, ISO 100 to ISO 1600 is 4 stops, so 5 minutes plus 4-stops = 18.75 secs. (cross fingers once again) Is that correct?


So I guess this is when knowing how ISOs affect HL headroom comes into play. What would be the lesson here?

[Daniel Browning]

So headroom really isn't some fluctuating range of tones, dependent upon the scene. It's really best defined as what the recording medium is capable of. Is that the right way to think of it?


In the case of film, that's correct: the headroom is built right into the recording medium. For example, a certain emulsion might have 6 stops above middle gray (headroom) and 6 stops below middle gray ("footroom") and that's it.


But with digital, it's a little different. You can put middle gray anywhere you want. So with 10 stops of dynamic range, you can have 3.5 stops above middle gray (headroom), and 6.5 below. Or 8 stops above and only 2 stops below. It's up to the raw converter. In practice, raw converters tend to put out 3.5 stops above, and 4.5 stops below, and stop there (8 stops).



And so Canon can choose to make f/2.8 have 3 stops at ISO 400, or it could've chosen something different. The way it is, with RAW converters tuned similarly, is no accident...


Precisely.



On a related note - does any of this discussion apply to shooting on a tripod?


Yes. Usually when you're on a tripod it's possible to "ETTR" so that the histogram is as far to the right as you want it. So there's no need to move on to the next step (ITTR).



Mr. Busch's book says, "Another way of adjusting exposure is by changing the ISO sensitivity..." and so on.


That's disappointing.



I've never used the long-exp. NR on my 40D. Do you think it's worthwhile using it? According to David Busch's book it's good for shutter speeds slower than 1 second, although you'll trade off some detail if you use it.


Yes, I think it's great. It reduces hot pixels and pattern noise, but it increases random noise a little bit. I can't think of why it would trade off any detail. (Maybe he's thinking of Nikon's long exp NR, which does eradicate small details.)



Would I have done better with a higher ISO and a faster shutter speed?


No, you did it right. Always do "ETTR then ITTR", never the reverse. Doing ITTR first would result in a lot more noise. Exposure is more important than ISO.

[canoli]

So the 10 stops of DR you speak of - is that what digital sensors are considered capable of capturing? Or is that the range that the visible world has? (or both?)


And when you say "you can put middle gray anywhere you want" and then later say "It's up to the raw converter" I'm not sure how those 2 statements go together. The first one I figured meant when we meter a scene, we're choosing the gray point. But if it's "up to the raw converter"...?


Doesn't our metering system take care of dividing the dynamic range? I thought that's what they all did, establish the 18% gray point (actually closer to 13% from what I've read) and then the 1/4 tones, 3/4 tones etc. fall where they may.


re: the book I quoted, yes, I wish I'd read a more advanced book first. I guess he's trying to keep it simple and just describe the effects of changing ISO - basically darkening or lightening an image capture. He says many times that "higher ISO means more noise" and I've taken that as gospel, since I've seen it so many other places too.


You need to write a book Daniel! (if you haven't already)


In any case, thanks for continuing the discussion. I appreciate it very much.

[Jon Ruyle]

So then it's strictly thermal noise that the long-exp. NR function addresses?


Yes. Well, almost. I believe it just takes a dark exposure of the same length and subtracts. This is primarily to reduce thermal noise, but it also must mitigate read noise as well (though if one wants to reduce read noise in a low signal image, more standard practice is to take several very fast exposures, combine eg by averaging, then subtract)



So with a tripod, is there ever a reason to boost ISO beyond 100, short of long (5-min.) exposures? (or even then?)


If the subject isn't moving and the tripod is sufficiently steady, then I don't think so. Thermal noise is less than linear, so longer exposure means better snr.



Although come to think of it, even at ISO 1600, what was a 5-min. exposure at ISO 100 is still going to be pretty long...something like...let's see, ISO 100 to ISO 1600 is 4 stops, so 5 minutes plus 4-stops = 18.75 secs. (cross fingers once again) Is that correct?


That's what I get [:)]



I can't think of why it would
trade off any detail. (Maybe he's thinking of Nikon's long exp NR,
which does eradicate small details.)


I assume the canon long exposure nr just takes a dark exposure of the same length and subtracts. Does Nikon do something different?

[Daniel Browning]

You're welcome.



So the 10 stops of DR you speak of - is that what digital sensors are considered capable of capturing?


Close to it. Engineers measure dynamic range from the clipping point down to where SNR reaches 1:1, which can be 11.5 stops on many cameras. But 1:1 is *very* noisy. Noisier than many photographers like to use. So how much dynamic range someone will use depends on their personal standard of how much noise is acceptable, especially pattern noise. You can find the "engineering" dynamic range for many cameras here:

http://dxomark.com/ ("http://dxomark.com/)



And when you say "you can put middle gray anywhere you want" and then later say "It's up to the raw converter" I'm not sure how those 2 statements go together.


It's both. You choose where to put it by changing the parameters of the raw converter (if it lets you).



The first one I figured meant when we meter a scene, we're choosing the gray point. But if it's "up to the raw converter"...?


Basically, it's best to "expose for the developer". In other words, think ahead to how the shot will be converted, then expose for that. If you know that you can move middle gray down, so that you get 2 stops more highlights for a certain contrasty shot, then you'll "underexpose" (compared to the AE meter) by two stops, but in reality you'll get just the exposure you wanted (perfect exposure).



Doesn't our metering system take care of dividing the dynamic range? I thought that's what they all did, establish the 18% gray point (actually closer to 13% from what I've read) and then the 1/4 tones, 3/4 tones etc. fall where they may.


That's right.



Yes. Well, almost. I believe it just takes a dark exposure of the same length and subtracts.


I think so too.



This is primarily to reduce thermal noise, but it also must mitigate read noise as well


It does help the "fixed pattern" part of the read noise, which is very beneficial, and it also takes care of the hot/dead pixels, but the random noise actually gets a little worse, because the read noises add in quadrature. If Canon used the technique you mentioned, it wouldn't add noise:



(though if one wants to reduce read noise in a low signal image, more standard practice is to take several very fast exposures, combine eg by averaging, then subtract)


Unfortunately, none of the popular raw converters support dark frame or bias frame subtraction, so I tend to just recommend the long-exp NR.



I assume the canon long exposure nr just takes a dark exposure of the same length and subtracts. Does Nikon do something different?


They have two forms of long exp NR. One is the same as Canon (dark frame subtraction), and can be turned off. The other is an algorithm that looks for hot pixels, and cannot be disabled. This is of course bothersome for astrophotographers, since stars tend to look a lot like hot pixels. There is a cumbersome workaround, though: if you *enable* long exp NR, then turn off the camera in the middle of its dark frame, it will cancel the dark frame subtraction, cancel the hot pixel killing software, but still save the light frame. Turning off the camera after every frame is too much work for me, though.

[Jon Ruyle]

Thanks for the clarification, Daniel.



Unfortunately, none of the popular raw converters support dark frame or bias frame subtraction, so I tend to just recommend the long-exp NR.



Iris does it I think, and it supports 5DII raws.



One is the same as Canon (dark frame subtraction), and can be turned off. The other is an algorithm that looks for hot pixels, and cannot be disabled. This is of course bothersome for astrophotographers, since stars tend to look a lot like hot pixels. There is a cumbersome workaround, though: if you *enable* long exp NR, then turn off the camera in the middle of its dark frame, it will cancel the dark frame subtraction, cancel the hot pixel killing software, but still save the light frame.


That absolutely sucks, and is a deal breaker for me since I like to take multiple exposures with a timer. Glad I decided to pull my 5DII out of the trash [:)]

[Daniel Browning]

Iris does it I think, and it supports 5DII raws.


Yeah, but it's not the kind of popular I was thinking of. It's also kind of basic on other features. Not a very advanced demosaic, etc. What I would really like is if programs could open raw files, make adjustments to raw values, and re-save a Bayer raw DNG file. I would love to be be able to:

Bias frame and dark frame subtraction in an IRIS batch script
Lens corrections in DxO Optics Pro (vignetting, distortion, CA, deconvolution, etc.)
Demosaic and everything else in RPP



I can dream.



Glad I decided to pull my 5DII out of the trash /emoticons/emotion-1.gif


:)