Saturday, July 9, 2016

Masses of Dynamic Range

So one of the virtues of "medium format" sensors is huge amounts of dynamic range. 15 stops! Holy crap.

Here's an serious question. What on earth do you do with that?

I know what I would do, which is to be even more slapdash with exposure than I am now, which is rather slaspdash. I'm pretty sure that's not what the people who buy digital MF systems are looking for, though. The point here is sort of the opposite of slapdash.

Output media are 10 stops, more or less at most. So you've got to map those 15 stops around a bunch, somehow. I guess you could do anything you like, but what do people actually do? Do you just fine-tune exposure in post, and then crush the extra stuff into the toe and shoulder rolloff, like film does for you automatically? Does it get rid of the "digital-looking highlights" thing for you for free?


  1. I don't own digital medium format, but I can offer a comparison between two different Nikon cameras, based on my own experience. This would be the D90 (5 years experience) and the D800 (1 year experience). Experience is based on 2 photographic outings a week on average. The D90 has about 12 stops of DR, the D800 about 14. On the D90, I used two kit zooms, on the D800 a 35mm f/2.8 PC Nikkor AiS. With both cameras, I shoot raw and develop in Lightroom CC using the "Camera Neutral" profile. Fine tuning and inkjet printing is done from Photoshop. Output size is up to 17x22''.

    Here are my observations:
    * On the D90, highlights are much better recoverable than on the D800. On the other hand, shadows drop to black rather quickly.
    * D800: Overexpose the highlights, and they're gone beyond rescue. The shadows, however, have a very long way before they go black. It is possible to open up shadows which the camera histogram displays as clipped to solid black, this without much noise and free of colour shifts.

    What do I do with all this? The target for my pictures is to be printed on paper, not to be viewed on a monitor. So there are around 6 stops available for output (not 10). I want the shadows to remain shadows, with just a bit of detail but not black, so I open them up a bit. Same with highlights. This I achieve with curves, often in local adjustments.

    With the D90, I knew that I could overexpose the highlights by one stop beyond clipping and recover them during conversion. This was to have enough data in the shadows so that they didn't go all black.

    With the D800, I just have to have an eye on the highlights; the shadows will come out fine in post.

    Bottom line: I, for one, prefer a non-digital look. This is achievable with both cameras, however it's a bit easier with the D800. I can't tell how much of this is attributable to the lens, though. Both cameras do a fine job at the given output size; a second hand D90 is a steal, and the kit lens is sharp, sharp, sharp.

  2. I would be very surprised if Ming's "14-15 stops" of exposure latitude is real and not just claimed.

    That said, it's my experience that medium-format digital files are generally much more malleable than those from smaller-format sensors; i.e., they can tolerate far more post-processing than most files before they start to fall apart.

    As for printing, I never had any problem squishing the files from my P30+ down to what my Epson 3880 printer could lay down on Epson Exhibition Fiber or Canson Platine Fiber Rag papers.

    I think "dynamic range" with cameras is like horsepower with cars: Few need or take full advantage of what they already have available, but nearly everybody wants more and will swear they really do need it!