Musings on Photography

And yet another word on lens differences

Posted in equipment by Paul Butzi on February 22, 2007

Mike Johnston writes here and Colin Iago writes here, about how digital seems to be ‘blanding’ all lenses together, so that differences don’t seem to be quite so apparent.

If true, that would seem to be interesting.  I’m not entirely convinced, and I think part of the clue lies in Colin’s words:

I’ve been fascinated to see how a lens with a highly distinctive character (like the CV 28mm Ultron) becomes just another competent lens on a digital body. And yes, it is the highlight rendering that changes, so Mike is probably right. Even if he isn’t it is a good working hypothesis for something that I’m definitely seeing.

Part of what I suspect is happening is that a lot of the people who used to worry about tonal properties of lenses were using negative film, and the switch to digital has turned things around.  It used to be that highlights went on forever, and shadows got clipped (unless you were using slide/reversal material), and now it’s the other way ’round.

And, I would observe: as sensor technology improves, the current lamentable highlight problems will fade.  Dynamic range will improve.  Rendering of highlights will get back some (or all, or even perhaps MORE) of the subtlty we had with film.  And when that happens, it may be that the distinctions we saw with film are back, only more so.

6 Responses

Subscribe to comments with RSS.

  1. Colin Jago said, on February 22, 2007 at 1:49 pm

    There is certainly some evidence that different (old, film) lenses show different shadow behaviour when used on a digital body. Sean Reid has published a few things about this and how that might affect a photographer’s preferences.

    These differences don’t seem to push the smile button though.

    I guess we are all only at the edge of beginning to understand this, and technology will move on as, or before, we do.

    For some subjects I prefer the bland lens effect in the highlights, but for others I miss the flutters.

  2. Doug said, on February 22, 2007 at 2:02 pm

    Paul, I’m not clear on how you see “dynamic range” and “highlights” being related, presuming that we’re talking about shooting Raw.

    With the Expose (to the) Right technique, you set the exposure to capture whatever highlights you want. Dynamic range will determine how much shadow detail you get (vs. noise), but it seems to my feeble mind that increasing the dynamic range doesn’t do anything about highlights.

    What am I missing here?

  3. Doug said, on February 22, 2007 at 2:20 pm

    Of course, having just hit the “Post comment” button on the prior comment I come across the White Paper on the new Canon 1DmkIII.

    Canon has added a custom function for “highlight tone priority”. This gives an extra stop of highlights by reducing exposure by one stop. I presume that this is automatically adjusted for during JPEG conversion, otherwise it’d just be a -1Ev exposure compensation. 🙂

    So that’s another example of why I’m confused.

  4. Ed Richards said, on February 23, 2007 at 5:08 am

    Dynamic range is critical to good highlights if you also want shadows, which Paul is probably assuming. So the “highlight tone priority” mode probably is just a -1Ev comp, since you could do the same when you process the raw files. Of course, it all depends on what you are comparing – digital beats slide film already. It is pretty limited compared to 4×5 Tmax 400, and that is before you do any compression processing. If you want to do a double exposure with a few stops difference with digital, you can merge the files in 32 bit mode and get as much DR as you want.

  5. Brandon J. Scott said, on February 23, 2007 at 5:31 am

    I may very well be wrong, but it seems to me that to get better transitions in the highlights with greater differentiation, we need to be using higher bit depths. I believe that currently many of the subtleties get averaged out in the analog to digital conversion. Of course as I said I may very well be wrong.

    Brandon

  6. Paul Butzi said, on February 24, 2007 at 9:09 am

    Paul, I’m not clear on how you see “dynamic range” and “highlights” being related, presuming that we’re talking about shooting Raw

    As Ed pointed out, it’s all about the total amount of detail. If you are (as I often find myself) worried about tonality in clouds, you ‘expose right’ and avoid clipping in the clouds. In order to do this, you drive the shadows down pretty far on the tonal scale of the exposure (but not necessarily of the print) which means that you get value compression in the shadows, which already suffer from quantization errors and thus need all the help they can get.

    If you had, say, 18 stops of dynamic range, this wouldn’t be an issue.


Comments are closed.

%d bloggers like this: