James A writes:
I was just reading the ETTR section. There is a lot of good information in there that I can hopefully put to use. My question: the article is about 5 years old, sensor technology has evolved somewhat during that time (I assume). Has this evolution changed your opinion on ETTR in 2017?
DIGLLOYD: the ETTR section in DAP is just as applicable today as when I wrote it.
In some ways it is even trickier, because some cameras (Nikon D810, Hasselblad X1D and others) make it very hard to be sure just how much headroom remains. These cameras and many others leave a stop or even two stops of headroom unused with their default metering as well as showing blowout when more than a stop of headroom remains (the Nikon D810 at ISO 64 is notoriously odd this way).
There is an incompetence in play with every camera vendor today: rather than a true raw histogram which would let the photographer see just what the sensor is capturing in each channel, every color camera manufacturer today shows an RGB histogram that bakes in all the JPEG camera settings along with a truncated color gamut of AdobeRGB or sRGB. This is just plain moronic. Alas. The net result is that a stop or even two stops of headroom go unused.
Below, the histogram from the Flowers at Russian Ridge example is nearly perfect, just 1/3 stop or so shy of maximal (maybe 1/2 stop if one can let just a few tiny areas blow out). RawDigger is an excellent tool for assessing whether the exposure is optimal.
First, keep up the great work! I really enjoy reading your articles and wish I had it in the budget to subscribe. Because I’m not a paying subscriber, I thought I’d pass a little info along to you regarding the 3FR/FFF files.
I’ve been shooting with the Hasselblad CF39 for years and learned pretty quickly that the shadows went to mud quickly if any attempts of pulling them brighter were needed. I always shot this back at ISO 50. One day I needed the extra speed so I shot at ISO 400. It was a fashion shoot and halfway through the sequence I must have changed the aperture or lighting because everything was completely blown out. Distressed, I loaded the files to the laptop and was easily able to bring the file back to a usable state using the exposure slider, adjusting the gamma, etc, and both shadow and highlights were fine. I was astonished and happily saved what was almost a ruined lingerie shoot. Later at the studio, I ran this over-exposure experiment at ISO 50 and no amount of over exposure was usable (highlights were simply lost). The same experiment at ISO 100 showed ample room for over-exposure by two stops and yielded beautiful shadow detail—even when pulled up. I’m sure I tested ISO 200 and 400 but the results must have been bad and I’ve never looked back.
Lately I’ve been freelancing at Christie’s in NYC and have been shooting the H5D40 and 60 in their studio. Turns out that the same thing happens with these digital sensors. The native is ISO 100, so shooting at ISO 200 and overexposing by two steps gives the best results—particularly with shadows.
This phenomenon seems to be baked into the Hasselblad DNA—as fas the CCD chips are concerned. I’m wondering if the X1D with its CMOS has the same DNA? If so, it might be something worth looking in to.
DIGLLOYD: unless there is something in Hasselblad that is unlike any other camera I’ve used in ten years, I would say that all of this is basically understanding exposure incorrectly, or rather—getting tricked by misleading metering and particularly misleading histograms. The solution is to use RawDigger to see what is really happening. The end result can in fact be the same as Cameron writes, because at higher ISO the camera “gains up” in a smart way. But for a true base ISO (not a “Lo” setting), there can be no advantage to this higher-ISO-overexpose theory, not that I’m aware of at least. This is why I consider it idiotic that no camera vendor offers a true raw histogram so the user can just see what is actually being captured, in a data/histogram sense.
P.S.: anyone who has the 'budget' to spend months or years instead of a day learning key exposure tricks is penny wise dollar foolish. I take pride in demystifying and showing what is actually going on—teaching effectively things that can baffle photographers for years.