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Expose to the right (ETTR) or underexpose?


Muizen

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In this Forum we have seen recently interesting discussions about metering and ETTR. As I understand it would be preferable to ETTR combined with checking for possible clippings in the histogram. However in Dpreview's "Leica Talk Forum" Guy Plat explains on Aug 9 that he prefers to underexpose to get more dramatic images with punchy colors. Guy underexposes his images by putting camera settings at EV -2/3.

I can't recall where, but I also read that ETTR is not advisable: one should aim at a histogram with most of the tones in the middle of the graph.

What is in your experience and opinion in general the best way to expose?

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ETTR makes most of the dynamic range of the camera and gives more "fill" to the shadows, thus lessening noise.

And punchy colors and drama? There is Photoshop for that...:rolleyes: The best file will give the most leeway for getting the look you want.

Underexposing for effect is an old slidefilm technique that, imo, has no relevance in the digital age.

Edited by jaapv
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Half the pixel info is in the highest zone; three fourths is in the highest two zones. Not like in the film days. Generally better to capture it IMO and have it there for PP if necessary. ETTR doesn't mean that the pic should printed as it comes out of the camera.

 

It also depends dynamic range of the scene, noise considerations, etc. But, generally speaking, I prefer to give myself more options to be creative after the shot, as long as I don't create undesirable effects in the process.

 

At the end of the day, whatever works for you to get the print you want.

 

Jeff

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Half the pixel info is in the highest zone; ...

Jeff,

 

Where did you derive these figures from please? The reason that I ask is that I had understood the weighting to be the opposite:o with more data assigned to the shadow areas, which is why it is:

a) possible to pull up shadow areas so much in post processing, and

B) a bad idea to blow the highlights because there is less data available there to salvage.

 

Pete.

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LuLa has a pretty good explanation of the idea behind ETTR at Optimizing Exposure.

 

I haven't seen the dpreview article, but I doubt that it refutes Reichmann's reasoning.

 

 

Howard,

 

Thanks for the pointer to the interesting article by Reichmann.

If and when do you think Leica should implement Reichmann's ideas as expressed in that article.

If any, what are the cons to his approach?

Also, what would be the reasons for Leica not to offer this approach as a choice?

 

The fellow, named A Guy Platt, is just playing around and asking for help/feedback.

He is not trying to refute anything.

 

Best, K-H.

Edited by k-hawinkler
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Jeff,

 

Where did you derive these figures from please? The reason that I ask is that I had understood the weighting to be the opposite:o with more data assigned to the shadow areas, which is why it is:

a) possible to pull up shadow areas so much in post processing, and

B) a bad idea to blow the highlights because there is less data available there to salvage.

 

Pete.

 

 

Optimizing Exposure

 

Your answer is in this article, it seems to me.

 

K-H.

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Optimizing Exposure

 

Your answer is in this article, it seems to me.

 

K-H.

Thanks, K-H, but the weighting distribution in the article is for a 'typical' dSLR. I feel sure I recall that when the M8 was released in 2006 it was discovered that the algorithm used to translate from a 12-bit to 8-bit raw file was weighted towards the darker end.

 

Pete.

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ETTR makes most of the dynamic range of the camera and gives more "fill" to the shadows, thus lessening noise.

And punchy colors and drama? There is Photoshop for that...:rolleyes: The best file will give the most leeway for getting the look you want.

Underexposing for effect is an old slidefilm technique that, imo, has no relevance in the digital age.

 

I completely agree. See also On Safari

 

The section near the end called "Avoid Tonality Suck-Out". Good sense!

 

Bill

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Pete, it's the compression algorithm in the M8-M9 that gives it a bit more shadow room, as I recall Michael Hußmann's LFI article.

 

Nonetheless, the electronics of the A/D converter place half the available brightness steps in the top level.

 

So although the M8/M9 isn't so strongly biased as the dSLRs, it fits into the same category. (Till Sandy or Michael straightens me out, anyway. :) )

Edited by ho_co
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... If and when do you think Leica should implement Reichmann's ideas as expressed in that article.

If any, what are the cons to his approach? ...

It's a fascinating idea and makes sense as Reichmann proposes it. But it goes against the Leica grain in that it is one more step toward letting the camera take over all parameters, rather than making the photographer think.

 

... Also, what would be the reasons for Leica not to offer this approach as a choice? ...

With a matrix-metering camera like Nikon and Canon, a lot of "experience" can be built into the electronics. Since the Leica rangefinders so far have a simple, single-cell metering system, it wouldn't be possible to build in another level of processing.

 

It could and should probably be done in a future EVIL body, but I doubt that it could be implemented in the M.

 

 

... The fellow, named A Guy Platt, is just playing around and asking for help/feedback.

He is not trying to refute anything.

Thanks for the correction, Karl-Heinz. My error. :o

 

 

 

Judging from how easy it is with today's dSLRs to get a good exposure without understanding why, and judging from the length of the forum threads from people asking for help with the M's metering, it may be necessary for us old-schoolers to pull in our horns and go to a metering system like the rest of the world. The R8 and R9 had already done so, of course. :(

Edited by ho_co
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Reichmann's article makes perfect sense. And I bet it works very well, IF you're photographing in situations where there's lots of light.

 

But I don't do that. I shoot mostly in the dark. At ISO 640 and f/1.4 there's never enough light to push the histogram to the right - I'm usually underexposed, or the subject is blurred beyond recognition by the slow shutter speed. So for me, ETTR is like a unicorn: a nice idea, but mythical.

 

Luckily, the M9 handles underexposure spectacularly well, despite the theory.

 

5993247894_8833e3e819_m.jpg

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Blakley,

 

Aren't you saying you ETTR as much as permitted by other more important constraints?

 

No, actually!

 

Even when there is enough light, I still expose per the meter or underexpose a little, partly out of inertia (I've been doing it a long time), and partly because that's the exposure that makes the image on the preview LCD look best. Now I realize that this is an insane practice (the LCD is a terrible guide to what the real picture is going to look like), but I've not managed to break myself of it.

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Jeff,

 

Where did you derive these figures from please? The reason that I ask is that I had understood the weighting to be the opposite:o with more data assigned to the shadow areas, which is why it is:

a) possible to pull up shadow areas so much in post processing, and

B) a bad idea to blow the highlights because there is less data available there to salvage.

 

Pete, you might be referring to the information covered in this article. Frankly, until you mentioned this, I hadn't heard of any uniqueness to the M8. But, even if this article is accurate, then the principle I cited remains, i.e., here 55% of the data is in the top 2 stops, while the top 3 comprise 70% (note that the stops are numbered backwards here...the higher numbers are the shadow areas as the text states).

 

The whole ETTR approach still applies, at least based on the technical premise that the bulk of the file data is stored in the higher stops (the highlights). Perhaps the M8 has slight advantage noise-wise if one needs to bring up the shadows in PP, but that's about it as far as I can see.

 

I'm sure there are folks on the forum more technically minded than I, but until shown otherwise, I don't know of anything that suggests the M8 operates counter to every source I've ever read on digital sensors, bit depth, etc, and I've read dozens.

 

Jeff

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No, actually!

 

Even when there is enough light, I still expose per the meter or underexpose a little, partly out of inertia (I've been doing it a long time), and partly because that's the exposure that makes the image on the preview LCD look best. Now I realize that this is an insane practice (the LCD is a terrible guide to what the real picture is going to look like), but I've not managed to break myself of it.

 

 

Hi Blakley,

 

Many thanks for your honest answer in which you also point out the difference between your practice and what you already have recognized to be a better way. I really appreciate your answer.

 

What I have slowly begun to appreciate by reading this forum and taking lots of images with my M9 and other cameras - but in a more and more similar fashion to the way I use my M9 - is this. The LCD in the back of the M9, although pretty poor, is good for two things, if and when it works, namely:

 

• Zoom in to check whether I got the precise framing boundaries when it matters, and

• Checking the histogram to find out whether I exposed optimally, more or less.

 

I also find the way images look on the LCD can be totally misleading. So I am ignoring that.

 

I have found that some of my images look totally overexposed both on the LCD and when I first look at them with Adobe Bridge and Photoshop although I have not blown a single highlight. In post processing then I get the image I want.

 

If I understood Mr. Reichmann's articles correctly, that can actually be the best way to proceed under certain degenerate circumstances.

 

Interesting. I always welcome additional constructive advice and pointing out errors in my thinking.

 

Thanks, K-H.

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Whether ETTR is a good idea or not depends on the sensor in question.

 

For the M9 the answer is that it is not. On the contrary, the M9 has far more latitude in the shadows than in the highlights. When in doubt it's much better to underexpose than overexpose. The highlights latitude of the M9 is extremely limited and overexposing with as little as a stop can result in blown highlights that you can't recover. Shadows are usually no problem and you can typically recover up to 4 stops with the only cost being added noise.

Edited by denoir
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Whether ETTR is a good idea or not depends on the sensor in question.

 

For the M9 the answer is that it is not. On the contrary, the M9 has far more latitude in the shadows than in the highlights. When in doubt it's much better to underexpose than overexpose. The highlights latitude of the M9 is extremely limited and overexposing with as little as a stop can result in blown highlights that you can't recover. Shadows are usually no problem and you can typically recover up to 4 stops with the only cost being added noise.

 

 

Thanks.

How about for the M9: ETTR but constrained by not blowing highlights (at least not by much, as explained in Reichmann's article)?

What would you call that approach?

 

Best, K-H.

Edited by k-hawinkler
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Very interesting discussion! I have read the article regarding ETTR, and number of times, and fully appreciate the significance of obtaining the best S/N ratio profile exposure from a scene. With a Canon 5DII, the ability to render information from shadows is very difficult, so ETTR is well suited, almost a necessity.

 

However with the M9, yes we do want ETTR, but with high dynamic range lighting, such as low light and highlights, or high dynamic lit landscapes, IMO it is more important that there are no blown highlights. The issue here is understanding the centre weighted metering of the M9, or having a good feel for the exposure just prior to clipping the highlights. Another issue is getting the right exposure with the M9 depends on the quality of lighting.

Edited by charles-k
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