Film versus digital, a noisy issue

[Epidic]

When I was getting into this stuff (that page above is from one of my first year college textbooks), that the folks actually taking pictures (the applied photo students) didn't give a rat's donkey about this stuff as they felt it had very little to do with the final image.

OK, so why should I care, or to use your words "give a rat's donkey", about what the photo students thought (or think). Just curious.

The point was that active photographers did not bother with the details of imaging science. Neither did it prevent good images from being made. So you can explore the details of image formation, but it is not going to necessarily be relavant to image making.

[rjlittlefield]

I enjoyed your essay and hope to see more.

That's good to hear. Collegial discussion is a good thing.

And since I find it hard to sit by and not comment, I expect that your hopes will be fulfilled!

--Rik

[rjlittlefield]

The point was that active photographers did not bother with the details of imaging science. Neither did it prevent good images from being made. So you can explore the details of image formation, but it is not going to necessarily be relavant to image making.

True enough. It's always possible to wander off into irrelevant aspects. I'm sure I do, from time to time.

But the real question always is (or should be), "What's limiting the quality of my work?"

In many types of photography, technology is not a limiting factor. If you're shooting landscapes or weddings, you're much better off spending your available brainpower thinking about lighting, composition, and how to get your subjects to smile Just So, than you would be wasting it on how to tune developer chemistry or exactly which raw converter to use, or for that matter whether to shoot film or digital.

In other types, however, technology often is a limiting factor.

If you want to make spherical panoramas, given current state of the art, you are going to confront technical issues of lens distortion, entrance pupil shift (with fisheye lenses), radial falloff and the associated color shifts with used with nonlinear sensors, and dynamic range limitations. It behooves the serious panographer to know enough about these things to at least push the right buttons and turn the right knobs on their favorite software.

Similarly, if you want to make pictures of small things, you are going to confront issues of DOF, diffraction, and noise, as a function of sensor size, f-stop, illumination level, and ISO rating. If you don't understand how these things are related to each other, then you're probably going to waste a great deal of time and money pursuing paths that, in the end, don't help.

I'm coming to think that the classic example of this is DOF & resolution as a function of sensor size. We see time and time again questions along the lines of "My point-and-shoot camera only goes to f/8. I'm not getting very much DOF. I know that DSLR lenses go down to f/22, and I know that larger f-numbers produce more DOF. Should I buy a DSLR to get more DOF?"

This is a completely reasonable question, and the best simple answer -- "No" -- is about as far from obvious as anything I've ever seen. The arguments are complex and difficult to follow. They're getting simpler, as we rephrase and reformulate them over and over again. Eventually, I hope, we'll figure out how to explain this fact so that it's intuitive to newcomers.

But the point is, we only became clear about this fact by "exploring the details of image formation". It makes little difference whether the person actually taking the pictures recognizes the relevance or not. Ignorance may be bliss, but it's still ignorance.

Come to think of it, the posting did specifically say "applied photo students". That in itself is at least a pink flag. In my experience, students have little if any valid basis for making that judgment, so it becomes the responsibility of the instructor to adequately convey what matters and what doesn't. If the students are being taught things that they consider irrelevant, then either a) the material really is irrelevant, and the instructor is wasting their time, or b) the material actually is relevant, but the students do not yet understand that. If (b), then one can (and should) ask, "Whose fault is that?". In my own classes, I teach only stuff that I consider relevant, and I do my level best to explain why it is. To what extent other people follow the same approach, I have no idea.

It all comes back to the photographer and his/her control.

I agree completely. Speaking only for myself, I find that I can control better those things that I understand. For me, there is great value in the details of image formation. It's how my images get formed.

I think the problem is that a digital image looks very smooth when enlarged implying it can be made larger.

This strikes me as a very important observation. From Will's description, it sounds like the author fouled up by taking a rule-of-thumb that's generally valid in one domain (film: smooth gradation implies high resolution, Polaroids notwithstanding) and applying it to another domain where it is emphatically not valid (digital: smooth gradation has nothing to do with resolution). But it seems to me that this example argues strongly in favor of paying attention to the details of image formation, not ignoring or sweeping them under the carpet.

--Rik

[Epidic]

Rik, I think we are basically on the same page.

About the applied students. I went to an obscure place called Rochester Institute of Technology. One thing going for it is it has a good photography program with a broad approach. The technical education was excellent, but they understood you can approach photography intuitively as well as logically. (The nice thing about photography is you can see the results.) Controlling detail is relavant in photography, but I don't think it matters if I calculate system MTF or approach the problem in simple terms to acheive my goals. Neither do I need to use a densitometer or the Zone System to determine exposure. Ansel Adams had a very technical understanding of the process, Henri Cartier-Bresson was very intuitive, both were very successful. RIT gave students a chance to learn about their craft on many different levels so students could build their own relationship to their craft. Knowing some of the alumni in the field from art photography to imaging science, I can say RIT did a good job.

[rjlittlefield]

Good school, good people -- there are many paths to greatness. It's what comes out the end that matters.

--Rik