[ds1848]

Hi. I am not sure whether or not this is the appropriate forum for this question, so please feel free to move it. I have a question for the board concerning the "expose to the right" maxim.

I make use of "ETTR" when I can in order to reduce shot noise in my pictures. I don't want to get into a debate about ETTR in general, as my question is a bit more specific.

Do you think ETTR is worthwhile when you have aperture and shutter speed set at your lowest acceptable limits? For example, let's say you have a shot metered at f5.6 and 1/60. You don't want to shoot any more open than 5.6 to preserve DOF/sharpness and you don't want to shoot any slower than 1/60 so as not to induce any blurring. You look at your histogram and see that you have latitude to ETTR by one stop, but, in this case, the only way you can do this is to increase the ISO, say from 200 to 400.

By ETTR you reduce the signal/noise ratio, but in the example above, at the same time you increase the amount of noise by moving from ISO 200 to ISO 400. Do these two things cancel each other out? Would it depend on the sensor in question, or would 200-400 be any different from, say, 800-1600? Or are these two effects (ETTR and increasing ISO) one in the same, meaning that ETTR is only relevant with respect to aperture/shutter speed at base ISO?

Thanks for the help and once again feel free to move this to wherever it is most appropriate.

[Ash]

This has been discussed a few times before on the forum.
I can direct you to some threads here:
Long discussion on this thread: https://www.pentaxforums.com/forums/general-photography/61775-expose-right.html
then more info in these:
https://www.pentaxforums.com/forums/general-photography/50026-expose-right-pr...histogram.html
https://www.pentaxforums.com/forums/digital-processing-software-printing/3741...then-what.html
https://www.pentaxforums.com/forums/pentax-dslr-discussion/98310-raw-jpeg-ettr.html


...and one on dpreview:
More boring high ISO / ETTR technodiscussion for the few of us who care [Page 1]: Pentax SLR Talk Forum: Digital Photography Review

Crux: probably little benefit from ETTR vs. exposing one stop lower ISO and 'pushing' exposure up one stop in PP, but is useful particularly if shooting in JPEG mode.

[Rupert]

It might depend on what the shot is to be used for? We sometimes forget that only a tiny fraction of us are Pros shooting for a Major Publication, and a little ISO 400 noise is sure not going to bother Old Granny if it is a shot of Little Johnny, is it? ISO 1600 won't bother her either........

I know you didn't ask, but ETTR will get you more bad shots than good over the long haul....from my experience. Blown highlights are not recoverable to any real degree, and the "edge" between just right and blown is too close for a histogram to get right most of the time. I know, some swear by it, but if you do it with regularity, you know that I am right. Just get it in the middle or a little to the right and current processing software can handle it from there......
Regards!

[ds1848]

Thank you very much for the helpful links. I was a bit confused, but the links confirm my suspicion. Basically, iso 800 +1 EV is the same as iso 400 properly metered. Maybe its different with jpegs, i dont know, but in raw, ETTR only makes sense at the base iso of the sensor. And of course don't clip.

Thinking about ETTR does help reinforce the idea that the problems we have with noise at high isos often have more to do with proper exposure than with the performance of the sensor itself.

Thanks again for the help.

[slinco]

It depends on what your goals are for ETTR - noise reduction or "getting all the bits". For me, with todays excellent RAW processing and noise reduction, getting all the bit's is the most important reason to ETTR, so yes, in your scenario upping the ISO would be beneficial, IMHO.

[Ash]

To me, in low ISOs it is less a concern, but depending on your camera, high ISO can lead to unacceptable chroma noise, which can compel you to shoot at the lower ISO and get the PP software to salvage as much detail as possible in pushing the exposure.

Consider the digital photography maxim of 'exposing for the shadows and post-processing for the highlights'.

[Rupert]

I've seen many shadows brought to life successfully, but am still waiting for someone to post a blown highlight that was corrected. You can't repair what isn't there....not even the mighty Canonites or Nikonettes can do that.
Regards

[JeffJS]

Even when you Are able to pull some detail out of the highlights, it will typically be white blobs with some glowing ring around it. A lot of people disagree and some even don't like it but I'm a strong advocate of Spot metering. Simply because it easily allows me to dictate what is properly exposed. It requires studying the scene a little bit to make your determination and setting your exposure accordingly. To make it work we have to remember What the meter is showing us.

Going strict ETTR, with a histogram is a mistake. Instead, once you understand what it is showing you, with respect to your scene, it can be a useful tool. I think howwever many people never bother to learn what constitutes exposure making the histogram, basically useless to them (in terms of getting the most properly exposed photo possible). Typically, people pick an Auto exposure mode and no amount of fiddling (to an extent) will change the actual exposure. The only way to Really control it is to go full Manual (M mode).

Not what you wanted in an answer probably so in answer to your question, No, I don't find value in worrying about where the histogram lies. It's location can be dictated by more factors than shutter speed and aperture. The histogram for This photo is all the way to the left, for instance.



This one is primarily to the left as well..

[Rupert]

I am hoping the next great advance in camera technology will be in the area of Dynamic Range. All the other areas are fairly well addressed in various camera models. If you need speed, it is there, if you need low noise, it is there, high ISO ...it is there....stability against camera shake....there too. The common weak spot is dynamic range.

Although it is very doubtful that sensors will match the human eye anytime soon, I have some thoughts that a camera with enough processing power will arrive and advance the current HDR effect of the K7 to a point that will give very natural results with little or no sign of the "cooked look" we now see in most HDR photos. If it is possible to do now with a good computer and software, and it is close, it won't be long until it can be done in-camera. How long? I would guess in the next 3-5 years at the outside.
This will change photography like digital itself did...even old Granny will be able to get properly exposed shots with only minimal effort. For shooters that now have to work hard against scenes with a huge difference in EV, they can concentrate more effort into composition and the other factors that make a great photo.
Regards