D810 blown highlights

From the mailbag:

After shooting with a d810 for an afternoon, I came away thinking that the sensor is blowing out i the highlights. After reading through your test, blogs, etc…am I to gather that my observations are NOT correct? I sold my d800e before the trial of the d810, and question if I should go ahead with the d810, or get another d800e. My primary use is in a controlled studio environment, documenting large paintings with a strobe set-up. Regardless of the differences between the two sensors, what I really would like to know is if the d810 can be set up to capture raw files that do not have highlight data that is blown out. Additionally, assuming the data is there, I want to know if it’s easily recoverable, and is NOT at the expense of a well exposed balanced file. From what I’ve seen thus far, there is not any raw file SW that seems to render files that have data in the upper highlights. Do you think that the camera is in need of a firmware adjustment to correct this situation?

IF not, what approach would you suggest that would allow the d810 to allow files that are not blown out looking? Any advice, insights by you would be greatly appreciated!

On one level, the answer is very simple. Blown highlights – defined as clipping of the right side of the raw histogram – is prima facie evidence of overexposure. Stop down, set a faster shutter speed, or turn down the ISO setting, Problem solved.

On a deeper level, things get complicated fast.

First off, as indicated in the simple explanation, the highlights may or may not be blown if they look blown in your raw developing program. To find out if they are indeed blown, or right–clipped, you need to look at the raw values. The best way that I know to do that is to buy a copy of RawDigger, and use it. If you’re quite computer-savvy and want something free, download DCRAW, and use it to convert raw files to TIFFs that you can examine in Photoshop or Lightroom.

As explained in excruciating detail in a series of papers on this site, your in-camera histogram doesn’t show you what the raw histogram looks like unless you take steps to get it to approximate the raw histogram. Fortunately, the un-tweaked in-camera histogram is conservative: for most subjects, under most lighting conditions it will tell you you’re overexposing before you really are.

Now, let’s assume you’ve looked at the raw files and see that they are well and truly overexposed. Put the memory card back in your camera and look at the in-camera histogram. Is it blown? If it is, you just overexposed. Next time take a test shot, hit play, and look at the in-camera histogram before making the exposures you wish to keep. It’s not blown in the in-camera histogram, but it is in RawDigger? If you’ve calibrated your in-camera histogram, you may want to do it over. If you haven’t, you’ve encountered one of those weird situations where the default settings for the in-camera histogram are not conservative. Note the situation – flowers are often problem subjects – and next time leave mpore room on the right with that subject and lighting.

There’s another situation in which you can blow highlights and have the in0camera histogram fail to show it. That’s if your highlight areas are quite small. The in-camera histogram doesn’t sample every pixel in the image; just every pixel in the preview JPEG, which is quite a bit smaller.

What if RawDigger says your highlights aren’t blown but Lightroom does, and applying Lr’s smart highlight recovery controls doesn’t give you acceptable results? Try another raw converter. My current favorite non-Adobe converter is Iridient Developer. It’s Mac-only, but it is an excellent program. Its main advantage over Lr, in my mind, is that the functions of all the controls are overt, not hidden. That makes it a little harder to use at first, but you can do things in ID that you can’t do in Lr. Also, ID often offers several different algorithms for an operation; you can try them all and pick the one that fits your situation the best.

As to whether a firmware change is likely to make any difference, I think not. I have seen no problem with the linearity of the D810’s tone curve near saturation, although some slight bending in the upper stop is normal. There have been reports that some of Adobe’s camera profiles for the D810 don’t produce good results. If you don’t want to use another raw converter than an Adobe one, trying different profiles, and/or waiting a few weeks may be a good idea.

If you’re operating at near base ISO, and you’re not doing heroic shadow boosts, you may not want to use the last smidgeon of the right side of the histogram until you get comfortable with your raw conversion process; you’ll still have quite a respectable dynamic range with the D810.

This topic is closely related to the area of exposure strategies. It seems like there are as many of those as there are serious photographers, and it’s way too much to cover here.