# Article to dig into at Luminous Landscape - Optimum exposure



## DominoDude (Oct 31, 2014)

Fairly new piece of text by Bob DiNatale -> http://www.luminous-landscape.com/essays/the_optimum_digital_exposure.shtml


Tags: Exposure, ETTR, Metering, M.A.P., Noise


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## AcutancePhotography (Oct 31, 2014)

Thanks for posting it. Lotta good stuff on that site.


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## DominoDude (Oct 31, 2014)

AcutancePhotography said:


> Thanks for posting it. Lotta good stuff on that site.


You're welcome.
Yes, I've had LL bookmarked for a long time, and revisit it quite often. On a grey and rainy day it's good to brush up on things I think I know, until I get them to a point where they should be.


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## Orangutan (Oct 31, 2014)

Seems like a long-winded way of saying "expose high, process low." I already use this method when I have time, and I have one quibble with his explanation: the goal, for me at least, is not to put the _brightest_ areas at 99+% exposure, but to put _the brightest areas I care about_ at 99+% exposure. In some cases I'm willing to allow some areas to blow-out, either because they're too small to affect the final image or because it's a trade-off I'm willing to make for the rest of the image.

And let me see if I can avoid derailment of the thread: sensor DR irrelevant here because no matter how much DR you have (current sensor tech) you can still apply these principles to optimize your exposure. Can we please not argue about sensor DR in this thread?


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## wtlloyd (Oct 31, 2014)

I've got an argument about that...


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## privatebydesign (Oct 31, 2014)

Orangutan said:


> Seems like a long-winded way of saying "expose high, process low." I already use this method when I have time, and I have one quibble with his explanation: the goal, for me at least, is not to put the _brightest_ areas at 99+% exposure, but to put _the brightest areas I care about_ at 99+% exposure. In some cases I'm willing to allow some areas to blow-out, either because they're too small to affect the final image or because it's a trade-off I'm willing to make for the rest of the image.
> 
> And let me see if I can avoid derailment of the thread: sensor DR irrelevant here because no matter how much DR you have (current sensor tech) you can still apply these principles to optimize your exposure. Can we please not argue about sensor DR in this thread?



Agree on all counts.

Though I have found that well over exposed very subtle evening skies cannot be lowered to accurately reflect the tonality of a more traditionally exposed shot, I have never learnt why.



wtlloyd said:


> I've got an argument about that...



Which bit? I am always up for a good argument discussion


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## DominoDude (Oct 31, 2014)

Orangutan said:


> Seems like a long-winded way of saying "expose high, process low." I already use this method when I have time, and I have one quibble with his explanation: the goal, for me at least, is not to put the _brightest_ areas at 99+% exposure, but to put _the brightest areas I care about_ at 99+% exposure. In some cases I'm willing to allow some areas to blow-out, either because they're too small to affect the final image or because it's a trade-off I'm willing to make for the rest of the image.
> 
> And let me see if I can avoid derailment of the thread: sensor DR irrelevant here because no matter how much DR you have (current sensor tech) you can still apply these principles to optimize your exposure. Can we please not argue about sensor DR in this thread?



Fixed the tagging. I included DR first because it's about making the best possible use of the dynamic range at hand/captured.
Author explains a method, and I won't go into nitpicking and semantics, but I automatically understood it correctly. It always have to be about what I consider to be optimum - for example should specular highlights be blown, sun rays reflecting in water should be blown. It's a method and a way of thinking. We have the responsibility to apply that method wisely and to think about what we're doing, and why we are doing so.


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## privatebydesign (Oct 31, 2014)

dilbert said:


> privatebydesign said:
> 
> 
> > Though I have found that well over exposed very subtle evening skies cannot be lowered to accurately reflect the tonality of a more traditionally exposed shot, I have never learnt why.
> ...



Most of them.


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## StudentOfLight (Oct 31, 2014)

Photography is a complex, creative process. To proclaim axioms as if everyone has the same creative goal is more than a little <please insert appropriate term because I'm a loss for words>.


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## privatebydesign (Oct 31, 2014)

StudentOfLight said:


> Photography is a complex, creative process. To proclaim axioms as if everyone has the same creative goal is more than a little <please insert appropriate term because I'm a loss for words>.



The suggestion isn't about everybody achieving the same end goal, it is about utilizing the hardware to give the most potential to realise that personal artistic goal. Capturing the maximum potential is to the benefit of everybody that uses RAW. Who cares about jpeg shooters! 

Besides, if you don't want to do it, don't, it doesn't alter the fact that an 'optimum exposure', as talked about in the article, is one that retains the most post processing potential.


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## zlatko (Oct 31, 2014)

Orangutan said:


> Seems like a long-winded way of saying "expose high, process low." I already use this method when I have time, and I have one quibble with his explanation: the goal, for me at least, is not to put the _brightest_ areas at 99+% exposure, but to put _the brightest areas I care about_ at 99+% exposure. In some cases I'm willing to allow some areas to blow-out, either because they're too small to affect the final image or because it's a trade-off I'm willing to make for the rest of the image.



I think the author says something similar in this quote from the article:

"There can be some red highlight warning in an optimum exposure if the photo includes sunlit bright snow, specular reflections, etc.. In the example above you might choose the middle +0.6 EV exposure, however, the red 'Highlight Clipping' on the roof in the first exposure, +1.3 EV, could also be used. The bright snow covered roofs in bright sunlight would look natural being 100% white with no texture. Remember the expression of the Artist’s Vision is what matters."

In other words, your expression of what matters is what matters.


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## meywd (Oct 31, 2014)

A great read, thanks for sharing, now I need to test it


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## Sporgon (Nov 1, 2014)

privatebydesign said:


> Though I have found that well over exposed very subtle evening skies cannot be lowered to accurately reflect the tonality of a more traditionally exposed shot, I have never learnt why.



That is what I find, and I believe the reason that that we are losing accuracy with that level of over exposure, especially saturation. 

I remember the original article produced by LL in 2002 regarding over exposure to achieve an improved raw file, and in those days they were dealing with( no surprise), digital tech from 2002, where tonal transition was poor compared with film, especially with CMOS, which was (IMO) inferior to CCD at that time. They were referring to the fact that if you did not have data recorded in the top one fifth of the histogram you were losing fifty percent of the potential information., which is correct in theory, but, doesn't deal with lose of accuracy and saturation. 

It is now generally accepted that to maximise the IQ potential in a scene that includes bright and dark you want to pull the recorded data across to the right as much as much as possible in order to preserve information in the dark areas, allowing specular highlights to blow etc; it's all sound practice. 

There is a benefit from over exposing a relatively small amount and then bringing the raw file back down in post. Look at the effect of pulled ISOs on SNR on some cameras. 

However in the recent article, suggesting that the optimum exposure for the black cat is the one on the right is just a load of bull. You might get away with it when the majority of the tones are black, but that doesn't mean it is sound technique. 

I took a couple of comparison shots to try and show what I mean, and have incorporated blue as it helps with the difference. 

The first picture (ending 5) is exposed using settings determined by an incident light meter. The matrix metering of the camera was wanting to overexpose by two thirds of a stop more. 

The second picture (ending in 6) is over exposed from the 'correct' exposure by two full stops. This was then reduced by two stops before converting the raw to 16 bit TIFF. Even with the pictures reduced for web display you can ( hopefully, I haven;t seen them yet of course) see the difference in the blue.

In the second two images, both at 50%, I have applied the appropriate curves and saturation, and then balanced the lesser exposed one in levels to equal them up. The loss of saturation in the blue bucket is clear, and I cannot get it back to being identical. 

The final two images are at 100% of the black buckets and there is no difference in 'IQ' or noise. Overall the correctly exposed image is the better one.


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## Sporgon (Nov 1, 2014)

Here are the second two after applying appropriate curves etc..


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## Sporgon (Nov 1, 2014)

And then the blacks:

To summarise, we have lost saturation in the lighter blue and have gained nothing in the smoothness of the blacks.


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## DominoDude (Nov 1, 2014)

Sporgon said:


> privatebydesign said:
> 
> 
> > Though I have found that well over exposed very subtle evening skies cannot be lowered to accurately reflect the tonality of a more traditionally exposed shot, I have never learnt why.
> ...



Hmmmm, interesting... (Which means that I'm thinking seriously about your findings, the consequences and how I would like to apply the result to my shooting style.)
There are times when I want somewhat punchy colours (at concerts, or in sunset shots for example), and underexpose deliberately already in camera. Experimenting with Magic Lantern, ETTR and this LL-article, because I also want to have the best possibility to change my processing mind afterwards in post.
My wallet and other circumstances has put restrictions on the tools I can use in post, so processing is done in DPP and that means all or nothing; no layers, no masks, no selective editing. I fiddle with all data I have in my RAWs at a time.
Need to find a new natural balance in my shooting style that works in the future as well as now.


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## Frodo (Nov 1, 2014)

Hi Sporgon
Thanks for the effort of posting those photos. I have the same experience that "over-exposure" or ETTR tends to compromise tonality in skies, well illustrated with your blue bucket (I use LR5). You comment that you have gained little in the black bucket. That bucket is providing you with sufficient shadow details for the image, because this is quite a low contrast scene. If, however, the blue bucket was in the sun and the black bucket in the shade, more exposure would have allowed you to capture more shadow detail. And in my case with a 5DII, reduced banding.
So its a case of deciding what is the priority (as you will already know!).
Nevertheless I'm not sure why tonality is lost in skies when exposing to the right as there should be more information at the right side of the histogram.


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## 2n10 (Nov 1, 2014)

Sporgon great work.

I think there is either less detail in highlights than claimed or that detail is so close to maxing out that we are seeing blowing out of the color even though the software can not recognize it. It would appear that blues may have a lower threshold of data to reach blowout zones?


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## privatebydesign (Nov 2, 2014)

Thanks Sporgon for illustrating my point, I did have a couple of early morning sky shots I had bracketed that I have used before to illustrate the difference, but your blue bucket works better!

Having read about it I think it is just the saturation levels, not the tonal values, but to have to go into the RAW file and apply tonal range based saturation curves seems a bit excessive seeing as how the black bucket didn't actually benefit from the exercise!

I find it interesting that there seem to be a small group of posters here that get their opinions from their own empirical results, we might not have the specific equation or technicality that causes the phenomena down pat, but we know what we see (though that often leads to accusations of fanboyism). It is a shame there is a much larger and more vocal group that rely almost exclusively on equations and theories to expound their opinions, generally until they own the relevant equipment and do an empirical test, and then their equations and opinions suddenly come more into line with the observations of the actual picture takers.


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## DominoDude (Nov 2, 2014)

Belated thanks from me also, Sporgon. Your shots were very useful.

I hope I don't have to feel like I belong in any special camp - other than the one trying to learn more, and the ones trying to find knowledge and methods to share.
I love my Canon gear like I love my left arm - it may itch at times, but I prefer to scratch that irritating itch over cutting the entire arm off.


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## Nelu (Jan 16, 2015)

All right, here is what I think about ETTR; I only shoot in raw and for landscape photography I almost always shoot for HDR, -2,0,+2, just in case the contrast is too big.
Well, quite often I get by only using the over-exposed frame (+2), and the overall quality is much better than processing the standard exposed frame.
Of course, there is the danger to have blown-out sky details but for those cases I simply use Photoshop to combine the two frames together.
Sometimes is just as simple as a gradient filter...

Cheers
Nelu


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## feanolas (Jan 21, 2015)

Funnily your greens and reds are obviously more saturated in the second picture, which is apparent on the background bricks and moss ! This is more in line with the theory of ETTR.
So we are speaking of a major imbalance in the treatment of the components.
Maybe your software is playing havoc with colours, trying to compensate for a known colour shift of the sensor in low light, but applying it in a range where there is no sensor coor shift due to the overexposure ? Just a wild guess...


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## privatebydesign (Jan 24, 2015)

feanolas said:


> Funnily your greens and reds are obviously more saturated in the second picture, which is apparent on the background bricks and moss ! This is more in line with the theory of ETTR.
> So we are speaking of a major imbalance in the treatment of the components.
> Maybe your software is playing havoc with colours, trying to compensate for a known colour shift of the sensor in low light, but applying it in a range where there is no sensor coor shift due to the overexposure ? Just a wild guess...



I think we have a different understanding of the word saturated. If you put a colour picker on the reds or greens they are more saturated in the top picture in all three sets. The 'correct' exposure is giving more detail and saturation than the severely overexposed image.


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## Sporgon (Jan 24, 2015)

privatebydesign said:


> feanolas said:
> 
> 
> > Funnily your greens and reds are obviously more saturated in the second picture, which is apparent on the background bricks and moss ! This is more in line with the theory of ETTR.
> ...



Thanks Private, yes that is what I would expect.

I believe blue is the weakest wavelength and this may have something to do with the effect ETTR has on blues, but other colours are effected in the same way. Not sure why feanolas thinks the second image has more saturated red, green etc. 

If you intend to lift shadows then a small amount of ETTR will improve the overall image, yes, but ETTR for the sake of it is a myth, and the article from LL that started this thread is absurd. 

I suggest anyone who believes in ETTR to 'improve IQ' try taking the same shot twice, one at correct exposure, the other two stops over. Convert to a JPEG and then have a look at the difference in size of the two files. 

Another point that I would make regarding exposure is printing. I have always found that the closer the exposure used was to a 'correct' incident light reading the better the picture prints.


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## sulla (Jan 24, 2015)

> Though I have found that well over exposed very subtle evening skies cannot be lowered to accurately reflect the tonality of a more traditionally exposed shot, I have never learnt why.



I also must admit that it happens to me, and likewise I don't understand why.
I've read Michael Reichmann's article on ETTR a loooooong time ago, and I feel I understand ETTR. It is not the difficult part to take the "optimum" ETTR-exposure, thanks to the RGB-histogram. But so far I've not found a working method to reduce the exposure in Lightroom back to the "proper" levels:

Just reducing the "optimum" exposure won't give an image identical to the camera "metered" one, so there must be a difference between in-camera-overexposing and in-Lightroom-exposure-reduction.

Likewise, reducing the "optimum" exposure and pushing the "metered" exposure won't give the same result. The saturations are off, as demonstrated in this thread, especially in skies etc...

So, additionally, playing around with the "highlights" and "whites" sliders doesn't let me achieve sameness between "metered" and "optimum"... Even if I push the "saturation" slider a bit...

It is a pity that Bob DiNatale does explain in detail how to capture the "optimum" exposure in camera, but does not explain how to achieve the "proper" expousre in software...

Perhaps I'm just too stupid...
But at least I'm glad I'm not the only one struggeling with it.

So, at the moment I stick to trying to achieve "proper" exposure already in camera. For my image-editing-capabilities this produces the best results most reliably.


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## feanolas (Jan 29, 2015)

I haven't used a color picker to check saturation, I judged by looking at the pictures in the second set. Anyway, the brick wall does not look like it has identical exposure in both pictures.
I am wondering how the OP has done his adjustments. I think that using sliders in any software is not going to produce a linear shift of the values. I haven't tested it yet, but the best bet would be to use the curve tool and shift linearly everything.


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## Sporgon (Jan 29, 2015)

feanolas said:


> I haven't used a color picker to check saturation, I judged by looking at the pictures in the second set. Anyway, the brick wall does not look like it has identical exposure in both pictures.
> I am wondering how the OP has done his adjustments. I think that using sliders in any software is not going to produce a linear shift of the values. I haven't tested it yet, but the best bet would be to use the curve tool and shift linearly everything.



They were not identical exposures, the second was two full stops over, then reduced two stops in DPP before converting to 16 bit TIFF. 

I don't use 'sliders' to alter an image, this was tweaked in curves to balance the appearance. A very minor adjustment but I can't remember now, and these files are deleted anyway. 

Using a small amount of ETTR is well established for assisting in a number of circumstances, and often something that I would do if faced with a single exposure shot of something in high contrast. However my point was made because of the LL article advising that the 'correct' exposure for a black cat in a coal hole is to expose the raw as virtually white, even given the date that this was produced.


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## Sporgon (Jan 29, 2015)

DominoDude said:


> I think the tonality "issue" when trying to lower exposure of a overexposed sky is due to the fact that the closer we are to clipping all the channels, the harder it is for an individual channel to stick out and be visibly dominant. When we, in post, drag our sliders down, we are stuck with values that's perceived as closer to a "tinted light grey" (240 240 255), than a "subtle blue" (170 170 185).
> 
> How about that as a thought?



I think it has something to do with blue being the 'weakest' or 'darkest' wavelength of light, and the camera processor is applying more amplification to blue. 

Certainly red and green are not as effected by overexposure, but it is there if you are extreme enough.


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## BeenThere (Jan 29, 2015)

I don't think most RAW conversions to an output file is linear. Ther is some roll-off of the highlights (highlight shoulder) that reduces hightlight contrast for the brightest highlights. This can explain why reducing highlights in software does not maintain tonalities.


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## privatebydesign (Jan 29, 2015)

BeenThere said:


> I don't think most RAW conversions to an output file is linear. Ther is some roll-off of the highlights (highlight shoulder) that reduces hightlight contrast for the brightest highlights. This can explain why reducing highlights in software does not maintain tonalities.



Linear RAW conversions look horrific! For the render to look close to lifelike a tone curve has to be applied, that is the gamma. Even our brain applies a 'gamma' curve to what we see, that is why it is necessary to do that to a digital file that has a linear capture.

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


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## photennek (Jan 29, 2015)

DominoDude said:


> I think the tonality "issue" when trying to lower exposure of a overexposed sky is due to the fact that the closer we are to clipping all the channels, the harder it is for an individual channel to stick out and be visibly dominant. When we, in post, drag our sliders down, we are stuck with values that's perceived as closer to a "tinted light grey" (240 240 255), than a "subtle blue" (170 170 185).
> 
> How about that as a thought?



If it would be this, then the solution would be to check on per channel basis that the chosen area in photo is withing the 99+%...? Instead of looking only at the luminosity values, that is. Although I don't know exactly how the luminosity exposure diagram is formed, but based on my experience with Lightroom they are not the same.


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## privatebydesign (Jan 29, 2015)

photennek said:


> DominoDude said:
> 
> 
> > I think the tonality "issue" when trying to lower exposure of a overexposed sky is due to the fact that the closer we are to clipping all the channels, the harder it is for an individual channel to stick out and be visibly dominant. When we, in post, drag our sliders down, we are stuck with values that's perceived as closer to a "tinted light grey" (240 240 255), than a "subtle blue" (170 170 185).
> ...



I have had the colour swatches open in a PS file for a few days and played with them.

Here is the answer. (In my humble opinion!)

If the R,G and B value is the same for a given pixel then they fall on the same point of the gamma curve, so in any three channel luminance adjustment the three are all moved the same amount along the gamma curve, so the tonality remains constant. if the R,G and B values are different on any pixel (coloured) then they fall on different points on the gamma curve, this means that any adjustment to the three values via shadows, highlights, exposure etc will alter each value a different amount, the lower values will come down more than the higher values. This changes the tonality of the image. 

The reason it is so prominent in the higher tones is because the differences along the gamma curve are at their biggest at the top of the exposure, midtones and darks are much closer together.


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## heptagon (Jan 29, 2015)

Magiclangern provides a button to "expose to the right". Adjust exposure in postprocessing to fit your needs. Problem solved, case closed.


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## privatebydesign (Jan 29, 2015)

heptagon said:


> Magiclangern provides a button to "expose to the right". Adjust exposure in postprocessing to fit your needs. Problem solved, case closed.



And how, exactly, do you do that? Because if you are using the 'Blacks', 'Shadows', 'Exposure', 'Highlights', or 'Whites' sliders you are not getting the tonality of the scene.

If you use tone curves on each colour channel seperately, if you are using the camera calibration panel etc then yu might be getting close.

You seem to be missing the point that 'simple' adjustments to an overexposed file do not get you back to the same tonality as a 'correctly' exposed file.


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## chauncey (Jan 29, 2015)

FWIW, my technique using my 1Ds3...always shoot in live view manual mode after moving all the 
in-camera picture style settings toward the left in an attempt to negate most of the jpeg nonsense 
displayed on the LCD screen. My goal is to have my RAW image open in Lightroom with the histogram 
closely matching what was displayed on my LCD's histogram.

This method has served me well when shooting "white stuff"/snow/egrets/white flowers as I generally 
end up with RGB numbers in the 245-250 range, ideal in my mind.

When I shoot tethered using Canon Utility Software hooked to my desktop, that histogram/exposure
needs to be backed off a bit as my images were being overexposed. Works for me.


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## AE1Pguy (Jan 29, 2015)

Until the camera manufacturers start to display histograms based on what will be captured with raw, rather than jpg, we're all to some extent kidding ourselves if we think we're exposing precisely in the first place. I've seen a couple of work around solutions ("UniWB" for example), but they all invoke other tradeoffs I haven't wanted to accept.

I mostly shoot landscapes, so I don't really care if my exposures are "accurate" or not. I just want as much SNR as possible. I'll most likely end up tweaking colors and manipulating brightness levels in post anyway. So for me, ETTR is the way to go. But, I can't go too far to the right, because I don't know exactly where the real clipping point will be, as long as the histogram is calculated on jpg capture.

I wish Canon cared about this...


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## privatebydesign (Jan 30, 2015)

AE1Pguy said:


> Until the camera manufacturers start to display histograms based on what will be captured with raw, rather than jpg, we're all to some extent kidding ourselves if we think we're exposing precisely in the first place. I've seen a couple of work around solutions ("UniWB" for example), but they all invoke other tradeoffs I haven't wanted to accept.
> 
> I mostly shoot landscapes, so I don't really care if my exposures are "accurate" or not. I just want as much SNR as possible. I'll most likely end up tweaking colors and manipulating brightness levels in post anyway. So for me, ETTR is the way to go. But, I can't go too far to the right, because I don't know exactly where the real clipping point will be, as long as the histogram is calculated on jpg capture.
> 
> I wish Canon cared about this...



Maybe Canon know that shooting like you do, to get the maximum SNR, is not the best way to get the highest IQ.


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## siegsAR (Jan 30, 2015)

I thought ETTR was the way to go; I've read a lot about it right after I got my 1st DSLR.

And after 5 years, I haven't really found a sound approach for it other than a "safety net" - a fix if there's something wrong that I can't wrap around my head on how or what to expose.

Sadly that's just what ETTR to me. Many times I wondered how could I not like it. Its just I always thought that if I could get the theoretical "proper" exposure for various scenes, that's everything for me, no ETTR, no optimizing.

I know that's just me though, also I'm relatively a starter in photography, I may or may not actively use it in the future. I don't hate it, I try it from time to time but until now it doesn't make a lot of difference.


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## bholliman (Jan 30, 2015)

Thanks Sporgon and PBD for sharing your experience and thoughts on this topic. I agree with your conclusions as they match my experience. 

After reading several ETTR articles last year I went through an "ETTR phase" where I was consistently exposing as far to the right as I could without clipping highlights in the camera histogram. I finally stopped after finding my picture quality was consistently suffering with this method and no amount of PP could bring back the correct colors and saturation to where they should be.


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## AE1Pguy (Jan 30, 2015)

privatebydesign said:


> AE1Pguy said:
> 
> 
> > Until the camera manufacturers start to display histograms based on what will be captured with raw, rather than jpg, we're all to some extent kidding ourselves if we think we're exposing precisely in the first place. I've seen a couple of work around solutions ("UniWB" for example), but they all invoke other tradeoffs I haven't wanted to accept.
> ...



Image quality? I rather doubt jpg representation if the ultimate arbiter of "image quality." The problems people are reporting are tone and saturation. Things easily changed in any editing s/w. But you can't bring back data that you never captured. How could having a better histogram representation of your raw capture be a problem either way? Even if you don't like ETTR, you could still benefit from more accuracy.


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## privatebydesign (Jan 30, 2015)

AE1Pguy said:


> privatebydesign said:
> 
> 
> > AE1Pguy said:
> ...



Accuracy in what? Accuracy in colour and relative tonal differences are nearly impossible with heavy ETTR, and virtually impossible to 'correct' in post even with good camera profiles. 

Have a play with Sporgon's bucket image and try to make the heavy ETTR image look exactly like the correctly exposed shot.

To be sure this kind of thing is a question of diminishing returns, and it seems some people and their images and workflow have more issues than others, are both bucket shots 'good enough'? Of course, but the correctly exposed shot is more 'accurate', and for some people in many situations that is more important than any perceived gain in IQ from having more shadow editability in post.


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## AE1Pguy (Jan 30, 2015)

privatebydesign said:


> AE1Pguy said:
> 
> 
> > privatebydesign said:
> ...



Accuracy in the histogram. Again, if you don't like ETTR, skip it. But there's absolutely no benefit to having your histogram calculated on the in-camera jpg preview, rather than off the raw data, especially if you're going to do some substantial manipulation of the raw file. That's all I'm saying.


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## chauncey (Jan 30, 2015)

> absolutely no benefit to having your histogram calculated on the in-camera jpg preview, rather than off the raw data


Au contraire mon ami...one can adjust the in camera picture style setting to closely approximate 
that RAW image. If you consider getting RGB numbers 245-250 close enough.


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## AE1Pguy (Jan 30, 2015)

chauncey said:


> > absolutely no benefit to having your histogram calculated on the in-camera jpg preview, rather than off the raw data
> 
> 
> Au contraire mon ami...one can adjust the in camera picture style setting to closely approximate
> that RAW image. If you consider getting RGB numbers 245-250 close enough.



I looked at that a couple of times. Never found a way that got very close to the raw histogram, unless I changed the settings so much that then the preview looked dramatically different than the subject. If you've got a link to a better method, I'll check it out.

But, again, what would be wrong with Canon just providing an option to calculate a raw histogram? I'm pretty sure one of the MF companies has been doing that for years, but I can't remember which one now. If it was just a custom setting, those of you who are satisfied with jpg histograms could have them, and those of us who want a raw one would be as well.


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## anthonyd (Jan 31, 2015)

Sporgon said:


> And then the blacks:
> 
> To summarise, we have lost saturation in the lighter blue and have gained nothing in the smoothness of the blacks.



Thanks for taking the time to do such an elaborate illustration of your point. However, maybe you don't see gain because your sensor didn't produce noise in the blacks in the first place. Is it possible to repeat your experiment with a much higher ISO? (I could try it myself, but if I post the results my crop sensor will spark DR arguments I fear, so I'll refrain).


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## Sporgon (Jan 31, 2015)

AE1Pguy said:


> unless I changed the settings so much that then the preview looked dramatically different than the subject.



Welcome to raw RAW !


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## Sporgon (Jan 31, 2015)

anthonyd said:


> Sporgon said:
> 
> 
> > And then the blacks:
> ...



Honestly, it wasn't that elaborate. It took all of ten minutes ! 

You are right about not producing noise in the blacks in the first place, but that is the issue with so many of these discussions regarding Canon 'IQ'. 

If the exposure was correct with high ISO, and the EV range was within the scope of the sensor, I don't see it would make any difference to the principle here.


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## heptagon (Jan 31, 2015)

privatebydesign said:


> heptagon said:
> 
> 
> > Magiclangern provides a button to "expose to the right". Adjust exposure in postprocessing to fit your needs. Problem solved, case closed.
> ...



The RAW data is linear. If you expose to the right, you just collect more photons. In software you have to reduce (or increase) the exposure by the same amount that you adjusted while taking the picture. Then you have the same raw data without blown highlights (when decreasing exposure taking the picture) or with less noise (when increasing exposure when taking the picture).

You do not need to change the channels separately. You do not need to change the tonality curve.

The required correction is only one single value. E. g. +2EV while taking the picture and then -2EV to reverse that effect in software.

That is the theory and software which does that is fine but there are many things that can go wrong. One big difference is the tonality curve of the camera (software) which is applied to convert linear RAW data to JPEG values. You cannot work with those JPEGs, you need linear RAW. But even then the RAW is preprocessed by software and that might do some things like change the color of dark/bright parts. E.g. reduce the color of dark parts to avoid color noise.

You can simply test your software. Switch to manual mode and take a photo of some dark objects before a dominant white wall and expose like the camera would do (make the white wall grey). Then expose to the right and remember how many EV you increased the exposure. E.g. 1/100s camera exposure vs 1/25s ETTR exposure = +2EV. Then use the RAW files and convert them with your software and apply -2EV exposure to the second picture. Now they should have EXACTLY the same color properties but the ETTR picture should have less noise. If not, your software is not up to that specific task.

Using the camera JPEGs here will lead to totally wrong colors, banding etc. due to all the "optimizations" applied to the RAW data in order to get good looking JPEGs.


At the end of the day the goal is to take a picture and to expose for that specific subject and the sensor noise may actually be low enough that you are satisfied with the exposure suggested by the spot metering of the camera. In that case you can directly use the camera JPEGs and be fine. Heavy postprocessing is only for low volume activities or people with too much time.


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## chauncey (Jan 31, 2015)

Oops...I made the erroneous assumption that anyone reading the LuLa article and basically subscribing 
to the ETTR mantra would be shooting for RAW capture and...doing his own PP. My bad! :


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## sanj (Jan 31, 2015)

chauncey said:


> Oops...I made the erroneous assumption that anyone reading the LuLa article and basically subscribing
> to the ETTR mantra would be shooting for RAW capture and...doing his own PP. My bad! :



  hahahaha


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## sanj (Jan 31, 2015)

heptagon said:


> privatebydesign said:
> 
> 
> > heptagon said:
> ...



I work 24/7 but still process my pictures to my satisfaction. Guess I have enough time for what I WANT in life.


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## Sporgon (Jan 31, 2015)

heptagon said:


> You can simply test your software. Switch to manual mode and take a photo of some dark objects before a dominant white wall and expose like the camera would do (make the white wall grey). Then expose to the right and remember how many EV you increased the exposure. E.g. 1/100s camera exposure vs 1/25s ETTR exposure = +2EV. Then use the RAW files and convert them with your software and apply -2EV exposure to the second picture. Now they should have EXACTLY the same color properties but the ETTR picture should have less noise. If not, your software is not up to that specific task.
> 
> 
> 
> ...



What a load of rubbish ! You have underexposed the White wall in the first place due to the failings of your camera (reflective ) meter ! Your 'ETTR' is only to get back to the correct exposure anyway.

I've said it many times; those interested in learning photography should get themselves an incident light meter and start to get to grips with exposure. (And the fact someone posts here suggests they are interested). 

As for 'the' spot meter reading, this is another exposure error give away. The whole idea of a spot meter is to take multiple readings. One spot meter reading is likely as not to be highly inaccurate.


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## privatebydesign (Jan 31, 2015)

heptagon said:


> privatebydesign said:
> 
> 
> > heptagon said:
> ...



RAW data is linear, all rendering software that actually gives us a realistic output image applies a gamma curve, it has to, it also treats green very differently to red and blue for all cameras with Bayer arrays.

Now if you had taken a couple of seconds to actually test your ideas you would know they do not hold true for anything other than black, white and grey.

As I explained in my earlier reply, when you have a coloured pixel the R,G,B values fall at different points on that gamma curve, now if you move all three values the same vertical distance on your exposure scale they move different amounts on the horizontal, numerical, scale, this means that the tone changes.

A couple of examples.

128.128.128 lowered three stops in post goes to 50.50.50 it is still an even toned grey just three stops darker.

Now try 170.170.185, note there is a 15 point difference between the two values, lower that three stops and you get 139.139.151, you now have a 12 point difference between the two values. THE TONE HAS CHANGED as well as the luminance.

Both tones and their -3 adjustments are shown below. As the tones get lighter in capture and the more you bring them down in post the more the impact.

When you work on darker tones the differences are too small to see, when you work on lighter tones, especially images with very subtle tonality like, as I first pointed out in the thread and Sporgon seconded, a nice bright but subtle toned sky, then you cannot get the true saturation and tonality close to how it looked if you do extreme ETTR as suggested in the original article.


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## climber (Jan 31, 2015)

privatebydesign said:


> .......
> 
> Now try 170.170.185, note there is a 15 point difference between the two values, lower that three stops and you get 139.139.151, you now have a 12 point difference between the two values. THE TONE HAS CHANGED as well as the luminance.



This could be solved if working in LAB color mode? I think so. Lowering three stops in "L" channel will leave "a" and "b" channel (which contain colors) the same.


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## privatebydesign (Jan 31, 2015)

climber said:


> privatebydesign said:
> 
> 
> > .......
> ...



That is an excellent idea, though there are issues associated with converting to Lab and back. So I tried it. It is much better, the difference only changed by a couple of points, but you have intrinsic issues of Lab.

But I have cracked it in RGB and I am going to do a problem image with it asap.

Do your curves-exposure etc adjustment, but use the Luminosity blending mode! Doing this maintains the 15 point spread on the above tone.

Maybe we can force extreme ETTR to work better, if so this could be a significant advance for some images.


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## DominoDude (Jan 31, 2015)

Loves how this evolves into something useful, inventive and constructive. Keep it up, guys!

A note on Lab: At those rare times that I've been using Ps, I've been doing my sharpening in Lab on the L-channel. Wouldn't mind hearing more about what pitfalls there could be in Lab.


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## chauncey (Jan 31, 2015)

Gonna talk real slow...Google YouTube> request tutorials on LAB in PS...https://www.youtube.com/results?search_query=using+lab+in+PS+CC


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## DominoDude (Jan 31, 2015)

chauncey said:


> Gonna talk real slow...Google YouTube> request tutorials on LAB in PS...https://www.youtube.com/results?search_query=using+lab+in+PS+CC



Mmm, thanks I really needed that. I'm known to be utterly dense...


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## feanolas (Feb 5, 2015)

privatebydesign said:


> climber said:
> 
> 
> > privatebydesign said:
> ...



Exactly my initial point: the software is probably not working linearly when adjusting exposure. A shame your solutions work only in PS, would be nice to have something that works in Lightroom.

Now I am wondering about your example: to keep the same tone in RGB, should I keep the distance (15 points) or should I keep the ratio (which is exactly 12 points). I think the ration gives the best tonality match.
To prove it, let's go extreme: if you drop to say 17, should it be 17.17.18 (same ratio) or 17.17.32. The latter is going to be a completely different tone, with almost twice the color component in the dominant.

Did I miss something?


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## tcmatthews (Feb 8, 2015)

heptagon said:


> privatebydesign said:
> 
> 
> > heptagon said:
> ...



This is why I almost never ETTR. I prefer to expose for the subject. It always seemed that after ETTR I could never get the colors and contrast right. They would always be flat. Then I would have to mess around with curves or color sliders. It was simply not worth the time. I could never make it look right and would loose patience in it. 

Most of my shots with my 6D are usable as JPEGs straight out of camera. (if I do not mess up.) But I still shoot RAW post process in LR. It is however generally minimal to just get back to the JPEG. 

The irony is that with my Sony cameras still I prefer ETTL.


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## Nelu (Feb 8, 2015)

tcmatthews said:


> This is why I almost never ETTR. I prefer to expose for the subject.



Interesting...And when you shoot landscape what is it that you consider your subject? The dark shadowed valley, or the brighter, green hills for example? What about the sky?


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## Orangutan (Feb 8, 2015)

Nelu said:


> tcmatthews said:
> 
> 
> > This is why I almost never ETTR. I prefer to expose for the subject.
> ...



I'd like to hear more about this as well. From my (admittedly limited) understanding of sensor design, you want the maximum exposure possible short of over exposure. ETTR can mean one of two things, one of which is useless.


Subjective ETTR: Use the maximum exposure that will not overexpose essential elements of the scene. In many cases (e.g. specular highlights and well-lit fog banks) there's not enough DR in any DSLR to capture the full tonal range in a single frame, so the photographer must make some judgements about which elements to preserve, or whether to use other techniques to control egregious tonal areas.
Ritualistic ETTR: look at the histogram and make sure the entire tone curve comes close to the right edge without going over. This is a sure way to sacrifice your main subject(s) on the alter of ritualistic technique. #2 works only when the entire scene is within the DR of the sensor.
ETTL is completely unsupported by the principles of digital sensor design.


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## tcmatthews (Feb 8, 2015)

Nelu said:


> tcmatthews said:
> 
> 
> > This is why I almost never ETTR. I prefer to expose for the subject.
> ...



It really depends on what you want your subject to be. Sometimes the sky is the only interesting thing so you expose for the sky. Other times it is the land or geological feature. The patterns the shadows make in the valley below. In general you must choose a subject. Often you have to balance out the sky and the landscape. Photographs are always more interesting when you have something to draw you in.

The difficulty comes in when you have an interesting scene that includes hard shadows and bright sky. In general you end up in a situation with two much dynamic range. Even ETTR there will be to much dynamic range. So you have to resort to braced shots then pic the best one, HDR in post or Dual ISO ML tricks. 

ETTR is a valid technique to maximize DR of the sensor. However what you really want is to control of the amount of DR in the scene.


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## tcmatthews (Feb 8, 2015)

Orangutan said:


> Nelu said:
> 
> 
> > tcmatthews said:
> ...



If I use ETTR at all it is subjective ETTR. In general I prefer to bracket out the shot in that case. I find often I use the bracketed shot just below my ETTR shot anyway. So I sacrifice some possible but hard to recover tonal areas. 

True, ETTL is not supported by principles of digital sensor design. But it is a valid technique especially if you want to produce high saturation, high contrast images with out touching those sliders in LR. You will need the entire scene with in the DR of the sensor. 

Remember ETTR is a technique. Do not use it ritualistically. Only use it when needed. I just find I do not like to use it much or need it.


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## climber (Feb 8, 2015)

Don't bother with ETTR. Simply make 2, 3 or 5 exposures and blend them manually in PP. Thus, you have each shot properly exposed for each subject (hill, sky, etc...)


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## heptagon (Feb 9, 2015)

climber said:


> Don't bother with ETTR. Simply make 2, 3 or 5 exposures and blend them manually in PP. Thus, you have each shot properly exposed for each subject (hill, sky, etc...)



Do you use RAW or JPEG for this?


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## BenKing (Feb 10, 2015)

I'm so confused. I read the article, and what I'm getting out of it is that we should overexpose our capture as much as possible, and that by doing so, we will have a "cleaner" image when we correct it back down in post. Is that what I'm reading? I'm new to this whole ETTL and ETTR concept, but I admit that many of my images, even at ISO 100 are still noisier that I would like.

However, I look at the "Optimum" example with the black cat, and if I overexposed my capture that much, there's no way I could get the detail back to the "Proper" photo. It looks like the detail on the cat's back is completely gone and blown out. Besides, both of those examples (bunny in snow, black cat against fake black background) are nowhere near as dynamic as the stuff that I always end up shooting, whether it be portraits or whatever.

So is the idea that we should push the exposure until _just before_ the highlights clip? As mentioned earlier in this thread, we should really be mostly concerned with the subject, though, otherwise it may be lost into irretrievable darkness.

Confused.


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## privatebydesign (Feb 11, 2015)

Ben,

Don't be confused, the article is not very good advice and what he is suggesting doesn't actually work.

But gentle ETTR does work, an up to one stop over exposure I find to work well, especially when shooting darker subjects with more emphasis on darker tones, much more than that and it becomes difficult to retain the colours and tonality of the original scene.

Of course you always have to watch for clipping, once your pixels register white they have no detail, but if you meter for a scene and make an EV adjustment for the subject, giving it an extra stop, so long as you don't clip too much, often works well for your darker tones.


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## climber (Feb 11, 2015)

heptagon said:


> climber said:
> 
> 
> > Don't bother with ETTR. Simply make 2, 3 or 5 exposures and blend them manually in PP. Thus, you have each shot properly exposed for each subject (hill, sky, etc...)
> ...



I always use RAW.


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## RLPhoto (Feb 11, 2015)

This article is meant for landscapes primarily but I've noticed ETTR with skin tones can be a very bad thing. I don't like to expose more than 1/2 of a stop over the correct metered exposure if they are light skinned and 1 stop of they are dark skinned. Skin tones get caulky and blotchy if you ETTR too much with them. 

ETTR has its place but not everything should automatically be ETTR.


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## privatebydesign (Feb 11, 2015)

RLPhoto said:


> This article is meant for landscapes primarily but I've noticed ETTR with skin tones can be a very bad thing. I don't like to expose more than 1/2 of a stop over the correct metered exposure if they are light skinned and 1 stop of they are dark skinned. Skin tones get caulky and blotchy if you ETTR too much with them.
> 
> ETTR has its place but not everything should automatically be ETTR.



That is because the red channel clips first and people images tend to have higher red channel levels, the green channel is the lowest because there are twice as many green pixels as the other two and nature shots (generally) have more green channel info, but it is balanced better with the red and blue so the IQ hit is not as noticeable. 

Tonality changes with ETTR, the higher you push the ETTR the more difficult it is to get the original tonality back because each channel is affected differently.


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## Orangutan (Feb 11, 2015)

privatebydesign said:


> That is because the red channel clips first and people images tend to have higher red channel levels
> 
> <snip>
> 
> Tonality changes with ETTR, the higher you push the ETTR the more difficult it is to get the original tonality back because each channel is affected differently.



Isn't that going beyond ETTR, though? The point of ETTR isn't to clip, or even necessarily to get past 98% for any channel on your subject; the point of ETTR is that you shouldn't have a chunk of void to the right of the tone curve (for the subject).


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## privatebydesign (Feb 11, 2015)

Orangutan said:


> privatebydesign said:
> 
> 
> > That is because the red channel clips first and people images tend to have higher red channel levels
> ...



You need to read the whole thread to get the relevance.

But the second part of the first sentence you quote is the important bit "people images tend to have higher red channel levels" not the clipping part.

The original premise is to do extreme ETTR such that nothing clips but everything is as overexposed as possible.

The problem with that is if a pixel has very diferent R,G abd B values they fall at very different places on the gamma curve, doing something as simple as lowering the exposure in post does not alter all three channel levels for each pixel equally, that is, the relationship between the recorded values and the new vales changes, this changes the tone, or colour, of the pixel, it makes it brighter and, generally, less red.

But depending on how discerning you are and the bit depth of your workflow these small differences can be seen on relatively gentle ETTR, though most of the time the improved shadow detail overwhelms the slight loss of accurate colour relationships.

Greys can be raised and lowered in post with impunity, all three pixels have the same value and any adjustment impacts each channel equally, but coloured pixels change tone (colour) as well as brightness when you raise or lower the brightness/exposure/shadows etc in standard post software techniques.


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## mackguyver (Feb 11, 2015)

privatebydesign said:


> Greys can be raised and lowered in post with impunity, all three pixels have the same value and any adjustment impacts each channel equally, but coloured pixels change tone (colour) as well as brightness when you raise or lower the brightness/exposure/shadows etc in standard post software techniques.


The biggest challenge of using ETTR in my experience are with strongly saturated colors of subjects like sunrise/sunsets, flowers, or similar subjects. If you push it too far to the right (even watching the RGB histogram), dropping the exposure won't bring the colors back.

For difficult exposures where the subject is based on my interpretation (e.g. landscapes), I tackle this by exposure bracketing (one underexposed shot with fully saturated colors), and then a strong ETTR exposure to the edge of the histogram. In post, I pull the shots up side-by-side and after lowering the exposure on the ETTR shot, I use the sliders to match the colors as close as I can to the saturated shot, referring to the RGB values as I go. It's not perfect, but helps me get cleaner noise levels in sillhouette and other low light photos.


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## Orangutan (Feb 11, 2015)

privatebydesign said:


> You need to read the whole thread to get the relevance.


OK, I'll go back and read it more carefully.



> The original premise is to do extreme ETTR such that nothing clips but everything is as overexposed as possible.
> 
> The problem with that is if a pixel has very diferent R,G abd B values they fall at very different places on the *gamma curve*, doing something as simple as lowering the exposure in post does not alter all three channel levels for each pixel equally, that is, the relationship between the recorded values and the new vales changes, this changes the tone, or colour, of the pixel, it makes it brighter and, generally, less red.
> 
> ...



Without more explanation this doesn't make sense to me. The individual photosites are linear with respect to exposure. If there is a non-linearity with respect to color channel then that's a problem with the raw conversion or other curves applied to the color channels. I would believe that a standard JPEG engine would do better with less than ETTR, but I'm not at all convinced for those who choose raw processing.

The way I look at, ETTR is the digital analog (pardon me) to Adams' zone system. I'll concede to anyone who knows the ZS better than I (that would be lots of people), but the general premise seems to be to look backwards from the final product:

1. How do I want the printed image to look?
2. How do I need to develop the negative to create #1?
3. How do I expose so I have a negative optimally suited to #2?

For digital it's similar, but there are no shoulders or toes, just a precipice at each end. We also know that lower tonal values in the scene will be noisier, and have less tonal gradation. It follows that the optimal "raw material" has as much light as possible for each important pixel, without going over the edge. How that's processed is a different question entirely.


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## eninja (Mar 5, 2015)

privatebydesign said:


> Ben,
> 
> Don't be confused, the article is not very good advice and what he is suggesting doesn't actually work.
> 
> ...



Thanks.. 
After I read this article from op, I tried set exposure compensation to above +1 and did check histogram for clipping, its a plus work. (previously I just set to +2/3 at most) - to preserve image quality (less noise) to maximum at high ISO.

Then I get a bit used to +1 and 1/3 compensation. Then on the last shoot, I found my photo clipped. 
Tsk Tsk Tsk!!!


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