Luminous Landscape Forum
Equipment & Techniques => Digital Cameras & Shooting Techniques => Topic started by: tonysmith on June 29, 2009, 10:49:11 am
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I found the following in the "Photography Tips" section of the website of the International Centre of Photography in New York:
Shadows and Highlights
This method applies to digital cameras, when capturing in the RAW format, as much as it does to film cameras. When shooting negative film, color, or b&w, the rule of thumb is to shoot for the shadows and develop for the highlights. What this means is: you should set your exposure meter so that you will capture all of the shadow detail that you want and process/develop your film to retain the amount of highlight detail that you want. Another way to say this is to overexpose your film as much as you need, and under develop it as much as you need.
How this works with digital cameras differs from film cameras only in the way you will process/develop the image file. When converting the RAW format you have the opportunity to bring detail back into the highlights just like you can when processing film.
—h. eugene foster, ICP instructor
Isn't this saying "expose to the left", contrary to the usual advice, or am I misunderstanding?
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Sounds like expose to the right to me.
This being the key line ...
"Another way to say this is to overexpose your film as much as you need, and under develop it as much as you need."
So expose to the right and hope you have enough headroom in the raw file to recover your highlights.
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Isn't this saying "expose to the left", contrary to the usual advice, or am I misunderstanding?
That's how I read it too so I'd agree with you, he's way off base. Film isn't linear capture like Raw, it has a H&D curve. They are not really remotely similar.
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I found the following in the "Photography Tips" section of the website of the International Centre of Photography in New York:
Shadows and Highlights
This method applies to digital cameras, when capturing in the RAW format, as much as it does to film cameras. When shooting negative film, color, or b&w, the rule of thumb is to shoot for the shadows and develop for the highlights. What this means is: you should set your exposure meter so that you will capture all of the shadow detail that you want and process/develop your film to retain the amount of highlight detail that you want. Another way to say this is to overexpose your film as much as you need, and under develop it as much as you need.
How this works with digital cameras differs from film cameras only in the way you will process/develop the image file. When converting the RAW format you have the opportunity to bring detail back into the highlights just like you can when processing film.
—h. eugene foster, ICP instructor
Isn't this saying "expose to the left", contrary to the usual advice, or am I misunderstanding?
No, it is expose to the right - meaning that the histogram of the image will have more peaks at the right end (higher exposure) than at the left end (lower exposure.
Peter
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No, it is expose to the right - meaning that the histogram of the image will have more peaks at the right end (higher exposure) than at the left end (lower exposure.
Peter
IF that's what he means, there are at least two of us misunderstanding his writing.
Film: Expose for the shadows, develop for the highlights (we've heard this for eons).
Digital: Expose for the highlights (ETTR, don't blow them out), develop for the highlights (render so you have the detail that's there).
I don't see how he can say the are similar....
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I don't degree that it's ETTR. With ETTR you expose as much to the right as possible without clipping important highlights. What they're suggesting is don't worry about the highlights when shooting and just expose for the shadows. Their assertion that you can bring back the highglights in RAW conversion just like you can when developing negative film is not really true. You can sometimes bring back partially blown highlights, but if all three channels are clipped there's nothing to bring back. Given that we generally tend to find blown highlights more distasteful than blocked up shadows when looking at an image, I would say their advice is not so good.
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This works with devloping b&w film where using the assuption that exposure determines the shadows and developement time controls the highlights works well.
With digital, if the scene brightness range exceeds what your camera is capable of recording you are totally screwed regardless how much you try and pull the exposure slider in your software.
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The original tip from the ICP is consistent with "expose to the right." He's writing it in a way that makes sense to photographers working with b+w film.
While it is true that digital is much more sensitive to highlight clipping than film, the basic idea of ETTR still works. One just has to be more careful about highlight clipping when making the exposure.
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Film: Expose for the shadows, develop for the highlights (we've heard this for eons).
Digital: Expose for the highlights (ETTR, don't blow them out), develop for the highlights (render so you have the detail that's there).
I don't see how he can say the are similar....
Well, they are similar really. When you expose film for the shadows, you are exposing to the right for digital; that is, making the highlights brighter. In both instances you would want the highlights as bright as possible w/o blowing them.
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Well, they are similar really. When you expose film for the shadows, you are exposing to the right for digital; that is, making the highlights brighter. In both instances you would want the highlights as bright as possible w/o blowing them.
There's no question that indeed ETTR is about exposing to get highlights you wish to record be as bright as possible without blowing them out. You don't expose for shadows with digital in that ETTR is about placing the most possible tones in the last stop which has, in a linear capture, the fewest bits with ETTR.
You've got a tonal scale that the sensor may or (most likely can't) fully capture. You either expose to get the shadow detail or the highlight detail if the range is farther than the capture device can record. In either case, one hopes to put the most bits in that last (shadow) stop. You might find that you'll lose highlight data in order to get that shadow detail but you must still calculate (expose) for the highlights in order get the bits in those shadows you wish to record. That doesn't mean you disregard shadows because in this example, you want that shadow detail. But you have to expose to the right up to the point that you can obtain the shadow detail as going the other direction reduces the number of bits in the area you want to record. Maybe that's where this fellow is suggesting "expose for the shadows" but its damn confusing and doesn't help in aiding the photographer from understanding that they have to expose as far to the right as possible in order to obtain those bits in the last stop of the shadows. His intentions might be in the right place but the communication isn't very good, two of us read it the opposite way.
Where digital and film are the same is, a photographer has to understand the scene range and the range the sensor or film is capable of capturing. But where they differ largely is where you place the weight on exposure. In digital, since its a linear capture, you weight on the opposite end where the shadows reside since in linear capture, the least amount of data is contained there and any "under exposure" results in more noise and less real data. Again, film's got an H&D curve. How's that affect shadows in terms of exposure?
So exposure weighting if you will, is different in film versus digital. And with film or digital, a photographer must know the scene range they have, the range they can capture and then decided which end they wish to keep or lose if its too large.
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His intentions might be in the right place but the communication isn't very good, two of us read it the opposite way.
Make that three of us (at least) that read it the opposite way.
In the Zone system (for film) one of course takes meter readings of all important areas, but only the shadow readings determine the exposure you should give. The high-zone readings are used only to determine the development (N, N+1, N-1, or something more extreme.)
"When converting the RAW format you have the opportunity to bring detail back into the highlights just like you can when processing film." This is patently false, if you "shoot for the shadows" as he suggests.
The rule of thumb, he says, is "shoot for the shadows and develop for the highlights. What this means is: you should set your exposure meter so that you will capture all of the shadow detail that you want and process/develop your film to retain the amount of highlight detail that you want."
And he concludes "How this works with digital cameras differs from film cameras only in the way you will process/develop the image file. When converting the RAW format you have the opportunity to bring detail back into the highlights just like you can when processing film."
My question to those of you that say this describes ETTR is: "What part of 'shoot for the shadows' don't you understand?"
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Well it certainly isn't expose to the left.
When he says "When converting the RAW format you have the opportunity to bring detail back into the highlights just like you can when processing film." which direction do you think he's adjusting the exposure?
I do not think of ETTR in terms of highlights. I think of it as giving me my shadows with less noise. So when I shoot ETTR I 'shoot for the shadows' but then I'm dumb.
edit: removed a word that bugged me.
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There's no question that indeed ETTR is about exposing to get highlights you wish to record be as bright as possible without blowing them out. You don't expose for shadows with digital in that ETTR is about placing the most possible tones in the last stop which has, in a linear capture, the fewest bits with ETTR.
You have it backwards - the last stop has the MOST bits, which is precisely the reason for ETTR. You want to place the entire tonal range of the image as high as possible on the sensor's response curve in order to preserve as much of the subtle tonal gradation as possible.
Peter
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When he says "When converting the RAW format you have the opportunity to bring detail back into the highlights just like you can when processing film." which direction do you think he's adjusting the exposure?
Adjusting exposure in the Raw converter? Perhaps. But its useless if you don't actually implement ETTR, there is nothing to "bring back". When you shoot using ETTR, the "normal" or default rendering in most converters produces an image that appears "over exposed" so you adjust the exposure to get the nominal rendering. "Over expose" too much, that's not going to happen of course. I don't see how this has anything to do with exposing for shadows or altering the rendering settings for such. Again, its possible he's talking about ETTR but its not clear and I don't think its a good idea to lump non linear film with linear Raw as being similar.
I do not think of ETTR in terms of highlights. I think of it as giving me my shadows with less noise. So when I shoot ETTR I 'shoot for the shadows' but then I'm clearly dumb.
That's a valid way to think of it. I do too but think of ETTR as exposing as close to clipping but not clipping highlight detail I wish to render. IOW, if I have a 8 stop scene and my camera can capture 7 stops, AND I want all the detail in the shadows, I have to forgo capturing that last stop of highlights via exposure settings. But I would use ETTR to get as much highlight exposure in the 7th stop in order to produce the most data in that first stop of shadows.
I see two issues here. One is targeting exposure for capturing the scene range assuming its greater than the sensor can record. 2nd is now targeting the exposure so that I implement ETTR based on this range.
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You have it backwards - the last stop has the MOST bits, which is precisely the reason for ETTR. You want to place the entire tonal range of the image as high as possible on the sensor's response curve in order to preserve as much of the subtle tonal gradation as possible.
Unclear semantics on my part. Last stop being shadows. When you expose to the right, you place as much data there as possible, the results being the most data one can record in the last stop (shadows) or if you prefer, first stop (shadows):
http://www.digitalphotopro.com/technique/c...ng-for-raw.html (http://www.digitalphotopro.com/technique/camera-technique/exposing-for-raw.html)
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You have it backwards - the last stop has the MOST bits, which is precisely the reason for ETTR.
Actually, ETTR really has nothing to do with "bits" and everything to do with more light....the reason ETTR works is NOT because of linear capture and data-dense packed highlights but because you are simply capturing more photons when you increase the exposure. More light = more photon...more photons = less noise. Simple as that...
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I think everybody is explaining the same technique, but looking at it from different ends. Some people are taking great care to get exactly the amount of exposure that will get the brightest highlights without clipping, which automatically gets you the most shadow detail (without clipping the highlights.) Other people are arguing that you should expose for shadow detail, but would also presumably not wish to clip highlights at the other end. Same thing, basically, badly phrased, perhaps. This is also assuming that nobody would want to completely blow the highlights in either film or digital, which can be done in either medium.
It's also possible to ETTL, and let the highlights go. This works in dark churches, where the blown highlights may give you a "spiritual-type" glow, while still letting you look at some of the details in the statuary, frescos, et. But you should know when you're going to let the highlights be blown...
I'm interested in the comment about the linearity of digital sensors, because it brings up the question of why somebody doesn't design a firmware tone curve for *exposure* that simulates a film curve (bring back my Kodachrome!) Shoulders are pretty damn useful sometimes.
Somebody's going to tell me it's been done, aren't they?
JC
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I'm interested in the comment about the linearity of digital sensors, because it brings up the question of why somebody doesn't design a firmware tone curve for *exposure* that simulates a film curve (bring back my Kodachrome!) Shoulders are pretty damn useful sometimes.
Somebody's going to tell me it's been done, aren't they?
When the image is shown in your Raw converter (unless you've asked for linear which may or may not be available), the curve results from the current rendering based on the current color space. IOW, you apply that tone curve when the image is output referred.
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I do not think of ETTR in terms of highlights. I think of it as giving me my shadows with less noise. So when I shoot ETTR I 'shoot for the shadows' but then I'm dumb
I think what Eric and I are saying is that ETTR is about placing your highlights as far right as possible without clipping highlights (highlights that you care about, anyway). While this does give you cleaner shadows, it is not exposing for the shadows. Placing the highlights is what determines your exposure, and the shadows fall whereever they fall. WIth digital cameras there's more latitude to bring up the shadows than there is to bring back clipped highlights, so digital exposure shares more in common with slide film than negative film.
Taken literally, the authors recommendation is to use a meter reading from the shadows to determine your exposure, without any regard to highlights at all. That is not exposing to the right; it is exposing for the shadows. The two are not the same.
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Hi,
To my understanding ETTR is about keeping noise down by keeping Signal/Noise Ration (SNR) as high as possible. As far I understand you need something like 100 photons captured to have a reasonable "photonic" noise. With to few photons we get som noise from statistics. So we want each sensor cell as filled as possible to keep sensor noise down. Lets assume that each sensor pixel can hold 50000 electron and that each photon yields one electron. So with the sensor cell near saturation we would have something like an SNR of 500 (50000/100). If we would be one stop below saturation Signal/Noise woul be 250, (50000/2/100) and so on.
So what we want to achieve is essentially to have the sensor nearly saturated in the highlights to get little noise in the shadows.
A couple of observations:
- In the silver halide days the expose for the shadows rule did only apply to negative film. Slide film should always be expsoed for the highlights, but with an eye always kept on mid tones.
- ETTR says essentially, don't care about middle tones or shadows. Lets's expose for minimum noise and maximum density range and fix the shadows and mid tones after the fact.
Now, if we happen to have a scene with a very wide dynamic range, like sunlighted clouds over a canyon in shade, we made need to expose for the clouds. That may cause mid tones to to dark which we need to fix in "development". The image will be darker than one exposed for correct mid tones, but it is the only way to keep good clouds, at least if we don't try with HDR/EDR.
Best regards
Erik
I think what Eric and I are saying is that ETTR is about placing your highlights as far right as possible without clipping highlights (highlights that you care about, anyway). While this does give you cleaner shadows, it is not exposing for the shadows. Placing the highlights is what determines your exposure, and the shadows fall whereever they fall. WIth digital cameras there's more latitude to bring up the shadows than there is to bring back clipped highlights, so digital exposure shares more in common with slide film than negative film.
Taken literally, the authors recommendation is to use a meter reading from the shadows to determine your exposure, without any regard to highlights at all. That is not exposing to the right; it is exposing for the shadows. The two are not the same.
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IF that's what he means, there are at least two of us misunderstanding his writing.
Film: Expose for the shadows, develop for the highlights (we've heard this for eons).
Digital: Expose for the highlights (ETTR, don't blow them out), develop for the highlights (render so you have the detail that's there).
I don't see how he can say the are similar....
Exactly. Examination of the characteristic curves of negative film and digital shows why film should be exposed for the shadows and digital exposed for the highlights.
With a typical B&W negative film, a minimum exposure is needed to record density above fog on the negative. This minumum exposure is not significantly affected by development. One should expose so that the deepest shadows where some detail is required will be above the fog level of the film. Development can help place the highlights and the shoulder on the curve (not well shown on the curve shown) will help losing the highlights. With high dynamic range subjects, the highlights might become blocked up and one might give less exposure to preserve them. Film tolerates overexposure better than underexposure.
[attachment=14988:TriX.gif]
With digital, there is no shoulder and the highlights clip abruptly. Clipping of shadows does not occur, but eventually shadow detail is limited by the signal to noise ratio. Normally, best results are obtained by exposing so the highlights are just short of clipping. With high dynamic range subjects, one might have to compromise, but clipped highlights are usually more objectionable than noisy shadows. Highlight recovery depends on intact channels (usually red and blue with daylight exposure), and one should expect to recover more than one stop. Digital degrades rapidly with overexposure.
[attachment=14989:ResultsGraph.png]
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Unclear semantics on my part. Last stop being shadows. When you expose to the right, you place as much data there as possible, the results being the most data one can record in the last stop (shadows) or if you prefer, first stop (shadows):
http://www.digitalphotopro.com/technique/c...ng-for-raw.html (http://www.digitalphotopro.com/technique/camera-technique/exposing-for-raw.html)
What you say is true but it's only part of why we ETTR. We want to get as much data not only in the shadows but throughout the entire photograph.
Peter
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I think what Eric and I are saying is that ETTR is about placing your highlights as far right as possible without clipping highlights (highlights that you care about, anyway). While this does give you cleaner shadows, it is not exposing for the shadows. Placing the highlights is what determines your exposure, and the shadows fall whereever they fall. WIth digital cameras there's more latitude to bring up the shadows than there is to bring back clipped highlights, so digital exposure shares more in common with slide film than negative film.
Taken literally, the authors recommendation is to use a meter reading from the shadows to determine your exposure, without any regard to highlights at all. That is not exposing to the right; it is exposing for the shadows. The two are not the same.
While you determine your exposure based on the highlights, the reason you do so is to get as much details (and as little noise) as possible in the shadows. In this sense you are exposing for the shadows.
Peter
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While you determine your exposure based on the highlights, the reason you do so is to get as much details (and as little noise) as possible in the shadows. In this sense you are exposing for the shadows.
Peter
Yes, this is how I "interpreted" what the guy was saying, although I will give the rest of you that his explanation was convoluted, to say the least. He could have taken a bit more time and written an elegant explanation taking the two methods at the same time. The reason I interpreted it this way is that any other way doesn't make sense, and the guy obviously knows photography. So I gave him the "principle of charity" in reading his explanation.
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Yes, this is how I "interpreted" what the guy was saying, although I will give the rest of you that his explanation was convoluted, to say the least. He could have taken a bit more time and written an elegant explanation taking the two methods at the same time. The reason I interpreted it this way is that any other way doesn't make sense, and the guy obviously knows photography. So I gave him the "principle of charity" in reading his explanation.
So what he said was both stupid and wrong, so he must have meant the opposite. Sounds a little like the defense some folks like to make of the "Your camera doesn't matter" guy.
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While you determine your exposure based on the highlights, the reason you do so is to get as much details (and as little noise) as possible in the shadows. In this sense you are exposing for the shadows.
Peter
You can choose to look at it that way if you want, but it's a misuse of term 'exposing for the shadows', and will cause confusion for photographers who are familiar with the term. There's a reason the term 'expose to the right' was coined; it's a different technique for determining exposure.
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You can choose to look at it that way if you want, but it's a misuse of term 'exposing for the shadows', and will cause confusion for photographers who are familiar with the term. There's a reason the term 'expose to the right' was coined; it's a different technique for determining exposure.
Perfectly stated. We're in total agreement!
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So what he said was both stupid and wrong, so he must have meant the opposite. Sounds a little like the defense some folks like to make of the "Your camera doesn't matter" guy.
I don't think what I said was that his writ was stupid or wrong.
What I said is that if the person knows photography, then he would not make a mistake like that. He may have written a sloppy explanation, but it doesn't mean he doesn't know what he is talking about. It's a simple matter of emailing him and asking if what he meant is how I and others interpreted it, or not.
I admitted it was confusing, but if you are exposing for the shadows and at the same time exposing in order to NOT blow the highlights, then the two methods seem to be interchangeable, with small discrepancies for film and sensor, respectably.
In other words, if you expose for shadows and NOT blow highlights, then you are exposing to the right in both cases. This is true because in each case the brightest you can make the shadows is limited of how far you can take the highlights before they blow.
Another way to put it is expose for the shadows w/o blowing the highlights: Wait! That's what he said. The confusion is that even if you expose for the shadows, you may not be able to properly expose the shadows without blowing highlights.
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The confusion is that even if you expose for the shadows, you may not be able to properly expose the shadows without blowing highlights.
No, no, no! That´s not confusion at all. It is perfectly accurate and it is not to be confused with confusion: it is Catch 22, the greatest catch of them all.
Rob C
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No, no, no! That´s not confusion at all. It is perfectly accurate and it is not to be confused with confusion: it is Catch 22, the greatest catch of them all.
Rob C
True, but that's what has everyone worked up. It is perfectly accurate because if you expose to the right as far as you can, then you've exposed for the shadows as much as you can. It's two sides of the same coin.
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He didn't mean 'Expose to the left', since exposing to the left, according to the histogram naming convention in digital photography would mean to take your histogram to the left as much as you can, and this is not what the guy is saying (he says expose as much as you need to have your shadows right). ETTL would actually be a stupid move without any other advantage than allowing fast shutter speeds, but regarding the quality of capture would be a ruin.
But he is not meaning 'Expose to the right' either, since he is not taking any care of not clipping the highlights in his advice.
So he is proposing a method to expose, that would be the opposite in conception to ETTR, but that cannot be called ETTL.
I wouldn't be too much interested in attending a seminar by Mr. Eugene Foster though.
Regards.
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I wouldn't be too much interested in attending a seminar by Mr. Eugene Foster though.
That's the best response so far!!!!
Look, you guys all seem to meander all around the basic facts and fail to get the basic fundamentals...more photons equals less noise...
Michael kinda got it wrong in his article...the ETTR really has nothing to do with "bits" and has EVERYTHING to do with PHOTONS!!!!
I can't say for a fact what the heck the original author of the opening meandering discussion about exposure was meaning to try to get across but the bottom line is if possible, give your sensors MORE PHOTONS. That's what ETTR is really all about. If you underexpose AT ALL and have to up-process your captures, you're making noise blossom. If you want reduced noise, expose more...give your sensor MORE PHOTONS!!!!
Can I get any more explicit? Do you get the fact that MORE PHOTONS is better for your signal to noise ration? That having more signal gives you less noise? Underexposing sucks...
Sure, you want to maintain the degree of highlight detail you need in the final capture...but don't look at your camera's histogram if you want any true guidance...look at your friggin' light meter!!!
Sorry, GLuijk is right...if this guy is actually teaching classes at ICP, I gotta think somebody should put a hit out on him...seriously, this crap only get everybody completely confused (and apparently willing to pay good money to take a class to get it all figured out).
Oih!!!
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I tend to agree with dwdallam -- that the guy probably knows what he's talking about, but wrote it badly.
I think Schewe overstates the argument. (He also states it badly, as did the guy who started the controversy.) You don't always want MORE photons, because then you'd have nothing but a white exposure, with everything blown; what you want is the OPTIMUM number of photons for whatever you're trying to do. You MAY want the MOST photons you can get without blowing the highlights. But maybe not -- in some photographs, you may choose to completely blow the highlights, because there's something in the shadows that's more important to get right.
This goes back to my dark church example. You may want to expose for the shadows and let the highlights go, something that happens when you are in dark places where flash is not allowed, but you'd like to get a sense of the colors. It happens in churches, museums, etc. If you are shooting, say, a great colorful painting in a dim gallery lit with clerestory windows -- not an uncommon situation -- you may want to let the window highlights blow so you can get the best possible, accurate, noise-free color in the painting. In this case, you don't care about the highlights: they're irrelevant. You may even crop them out later. In effect, you're exposing for the shadows. So, I don't think that idea is in any way stupid or wrong, it's just not the conventional use of a camera in catching a landscape. (Though sometimes the same thing comes up in landscapes, when you choose to deliberately blow the highlights, particularly if you're shooting close to the setting sun, but don't want the sun, only the raking shadows.)
In fact, I'd say that perhaps in a majority of indoor photos where flash is not allowed, but where there are cracks or small windows or reflections or other hot lights, but where the main action is in shadow -- a wedding -- you may be much more interested in the shadows than in not blowing certain highlights, which, in effect, act like specular highlights in a normally exposed photograph. That is, they are completely blown, but nobody cares, because they are small and irrelevant. In a very dark church I can easily imagine choosing to blow background candles in order to get a little noise-free color in the bridesmaids' dresses...
On another matter, I appreciate Andrew Rodney's attempt to explain to me about shoulders, but there were several words in the explanation that I didn't understand.
JC
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Michael kinda got it wrong in his article...the ETTR really has nothing to do with "bits" and has EVERYTHING to do with PHOTONS!!!!
I can't say for a fact what the heck the original author of the opening meandering discussion about exposure was meaning to try to get across but the bottom line is if possible, give your sensors MORE PHOTONS. That's what ETTR is really all about. If you underexpose AT ALL and have to up-process your captures, you're making noise blossom. If you want reduced noise, expose more...give your sensor MORE PHOTONS!!!!
Can I get any more explicit? Do you get the fact that MORE PHOTONS is better for your signal to noise ration? That having more signal gives you less noise? Underexposing sucks...
While it is true that the signal to noise ratio is largely determined by photon counting statistics, one must remember that a sensor can effectively record the maximum number of photons only when it is used at the the base ISO. For each doubling of the ISO setting over base, the maximal number of collected photons that can be collected without clipping in the analog to digital converter is halved. Proponents of ETTR are concerned if their histograms fall a half stop to left at base ISO, but think nothing of shooting at double or even quadruple the base ISO as long as the histogram is snugged up to the right or the exposure meter indicates "proper" exposure for the ISO for which the camera is set.
When depth of field or motion freezing considerations require the use of a higher ISO, dynamic range does not suffer as much from the reduced number of collected photons as would be expected from photon counting statistics alone, since the read noise is reduced at higher ISO with current dSRLs. Read noise is the predominant source of noise in the deep shadows, and what one loses at the high end is recovered in part at the low end. However, as ISO is increased further, improvements in read noise reach a maximum. For example, with the Canon 1D Mark III, it makes no sense to increase the ISO beyond 1600 as explained here (http://ttp://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p3.html#ETTR). After that point, one should increase the effective ISO with the raw converter, thereby obtaining increased headroom in the highlights, even though the histogram will be to the left. However, the JPEG preview shown on the camera LCD will appear dark.
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Still don't know any more than I did before reading through this thread.
No one yet has shown through real world images the advantages of ETTR.
More photons? Of course you want more photons. It's called letting more light in. The problem with that is digital sensors are unpredictable in letting you gauge what light is available and how it will be captured because sensors don't behave the same way our eyes respond to light. Sensors respond and record how much light is REFLECTED BACK from how many DARK and LIGHT objects are contained in a scene regardless of how much overall light is in the scene.
This becomes quite clear when shooting a high contrast scene for example a frame equally composed of a sunlit concrete sidewalk and a tall cedar fence with shrubbery in shadow at its base. I guarantee you'll be using two drastically different exposures when equally including both the dark fence and the sidewalk compared to having about 80% of the frame taken up by the dark cedar fence. Even if you ETTR that fence and let the small portion of sunlit sidewalk clip to white, the fence is going to have noise no matter the ISO setting. I get this with my Pentax K100D DSLR all the time.
On the other hand I was shooting this same scene with diffused light from a cloud that happened by covering the sun that required drastic exposure changes by comparison to how my eyes perceived the amount of light that had been reduced. I shot other outdoor scenes in similar situations shooting two frames of the same scene with the same exposure where with the second frame the edge of a cloud just slightly obscured the sun in a way my eyes didn't notice a change in light level but caused the histogram in ACR between the two shots to move from the 1/4 zone to just slightly left of the mid zone. That's a big jump to have to compensate for when capturing quick shots.
So from all this IMO ETTR is too much of a hassle having to out think the camera's sensor in how it sees and captures light combined with gauging the moving target of changing light levels and predicting when and if clipping occurs.
And another question that comes to mind is are you suppose to ETTR a low lit scene whose ACR histogram would normally fall just slightly left of the 3/4 zone if choosing an exposure to make the preview look correct in ACR. Are we to overexpose that kind of scene to make ACR's histogram move to the middle? 1/4 zone? Where? How much ETTR for that scene?
I've ETTR'ed such a scene and I didn't get any more noise in the shadows than I did if I hadn't ETTR'ed when normalizing the look of the scene in ACR.
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It's a common misconception that ETTR is the answer to every exposure situation. ETTR really only makes sense when the contrast range of the scene you're shooting easily fits within the dynamic range of the camera.
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It's a common misconception that ETTR is the answer to every exposure situation. ETTR really only makes sense when the contrast range of the scene you're shooting easily fits within the dynamic range of the camera.
How does one gauge contrast range to match the dynamic range capabilities of a camera's sensor shooting out in the field? Is there a DR to contrast table calculator for each sensor from the guys at ISO? What does that look like?
I need to shoot pictures at an exposure level that requires the least amount of post processing possible. If I nailed it in camera what difference does it make if I ETTR'ed since ETTR's benefit is to reduce noise that would be increased and corrected through edits if I hadn't ETTR'ed? And I don't see that much of change in noise levels either way.
Dynamic range gauging and matching sounds like another moving target to me and way too much work and thought required than it's worth.
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Jeff,
Saw you are a Texan and checked out your Garner State Park shots. I think you and I may have passed each other since I was there about the same time as your Fall of 2008 pix indicate. The colors in your well composed images show a clearly different and nicer looking point of view than my somewhat dull looking Pentax PEF's shot of the same area.
Nice work.
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How does one gauge contrast range to match the dynamic range capabilities of a camera's sensor shooting out in the field? Is there a DR to contrast table calculator for each sensor from the guys at ISO? What does that look like?
How do you match the dynamic range capabilities of a camera's sensor shooting out in the field? Do you wait until a cloud covers the sun? Short of "coming back another time", one has to live with the dynamic range of the scenery and make the best of it. The latter includes the decision sometimes about what to sacrify: the very highlights or the very shadows.
Except if the dynamic range of the scenery is clearly less than the camera's capability, accurately or close to accurately seeing the raw exposure is critical, and that is not possible without a special neutral setup coaxing the camera into displaying histograms, which are closely resembling the raw histograms. There is at least one MFDB, which does display raw histogram (I forgot which one, but someone posted this on LL), but otherwise you have to fool the camera.
I need to shoot pictures at an exposure level that requires the least amount of post processing possible
Well, then ETTR is certainly not for you.
If I nailed it in camera what difference does it make if I ETTR'ed since ETTR's benefit is to reduce noise that would be increased and corrected through edits if I hadn't ETTR'ed? And I don't see that much of change in noise levels either way
If there are underexposed areas in the image, then the noise is there, it can only be suppressed. If the result is good enough for you, then you are right, you have no reason to care for this aspect.
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Sure, you want to maintain the degree of highlight detail you need in the final capture...but don't look at your camera's histogram if you want any true guidance...look at your friggin' light meter!!!
And there lies a problem. I have done that using guidance from the Minolta Flashmeter that I have, and I get a reading that works well when copying a painting (my own, relax) with bright highlights such as white or silver. Also, the camera´s matrix metering works closely in harmony with what the Minolta says. But, remove those highlights (different original painting) and then the same incident light reading no longer fits the matrix reading nor the ETTR histogram. So, in effect, digital capture is far less reliable/simple to nail than is transparency material.
Perhaps, in the end, one should forget ETTR and just go with the matrix metering and look at the flashing highlights mode instead of the histogram.
On the understanding that transparency films were never going to do both ends of the range justice at the same time (normal subjects), then perhaps the problem is not digital capture but rather what we imagine it should deliver. If we can accept that nothing in life is going to be perfect, perhaps using digi capture will become more pleasant and just as fast/simple to get "right" within what can be achieved. Perhaps yes; perhaps not.
This, of course, would only apply in cases where you want to make a single exposure of your subject and not a selection for afterwork.
Rob C
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There is at least one MFDB, which does display raw histogram (I forgot which one, but someone posted this on LL)
all Phase One Backs show the histogram with "linear response". There is only rudimentary software in the backs to show "something" on the display and this is the capture without tonal curves. There is an icc profile appiled that reproduces a neutral grey axis that is a TRC of gamma 1.8. But the histogram on the back and the RAW file in Capture One match exactly if you set the so called "film curve" in Capture One to "linear response" (in this case there is no correction of gradation or whatever).
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the histogram on the back and the RAW file in Capture One match exactly if you set the so called "film curve" in Capture One to "linear response"
This is a bad sign. I don't know C1, but I guess it does not display the raw histograms.
You can test this: shoot the very same scenery with vastly different WBs, like incandescent vs. fluorescent. If the displayed histograms change, then they are past WB application, thus not representative of the raw channels.
It is important to understand, that linear vs. color space curve histogram changes how far the histogram reaches at a certain level, but it does not change when it arrives at the right edge and indicates clipping. For example the linear histogram ends at the middle of the range if the exposure is 1 EV under raw clipping; the sRGB histogram is much farther to the right at the same exposure. Increasing that exposure by 0.5 EV expands the linear histogram to the 3/4 point, the sRGB histogram changes only a bit - but they both indicate clipping at the same exposure.
Both the WB application and the color space conversion affect the appearance of histograms a lot, no matter if linear or not, and both are rendering the histograms non-representative of the raw channels.
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This is a bad sign. I don't know C1, but I guess it does not display the raw histograms.
you are right: it's not the RAW histogram.
However this is not "bad" - actually it's extremely consistant. The histogram on the camera shows exactly the histogram I see in C1 when no (so called) "film curve" is applied. As you always work with an input profile specifically for your camera in C1 it actually makes a lot of sense to display the profile corrected histogram on the camera. At least in the case of Phase One digibacks it makes sense... with DSLRs it's unavoidably different.
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According to my experience clipping happens in RAW between +0.5 EV +1 EV respect RGB in the B or R channels, due to the colour space application and the WB correction. For this reason it is usually possible to overexpose if we want to improve the shadows while keeping the highlight information. We can ETTL if we have enough DR or ETTR if not.
In any case the RAW file process and the final image have to be HDR like, if we pretend to keep the original colours.