gdanmitchell
Offline
• • • • • • •
Upload & Sell: Off
|
 p.8 #6 · Utility of dynamic range beyond a certain point | |
chiron wrote:
It's an interesting problem. The lighting ratio in the actual scene is vast--I can't even guess it--and is way beyond what any sensor or the human eye can record. For example, if one comes from a dark room into sunlight (as in the old days, from a movie theater into afternoon sun), you can't see for a bit until your eyes adjust to the light. And if you then go back into the darkened room, you again can't see there until your eyes adjust. We can't see bright and dark at the same time.
So, you are trying to render the scene in a way that in fact it is never seen by human eyes, by compressing the lighting ratio after the fact. Painters do this all the time and make it look natural, in part through the varying colors and the varying intensity with which they depict colors in the painting. My own experience is that it is very hard to do this in photography without the result looking artificial and unnatural--because it is artificial and unnatural for our eyes to see it that way....Show more →
we
I know that a lot of people — including you, clearly — understand this about photographing subjects with very large dynamic ranges. But I’m still surprised by how many photographers and photography enthusiasts don’t get this basic fact about making photographs… and they assume that we can somehow make the kinds of photographs of these subjects that we are used to seeing while avoiding the necessity to make adjustments (sometimes quite large adjustments) in post to deal with the gigantic dynamic ranges.
They seem to think that it is just a matter of using a camera that captures a large dynamic range and… job done.
The trick is that the capture system creates something that looks little at all like what we see when we look at the original subject with our own eyes (and brains). Quite simply, the camera does not see at all like the human visual system sees.
The (wrong) notion seems to be that if you just use the right camera and all of the right settings that you should simply be able to “capture reality” without “manipulating” the image later on. It rarely works that way.
In order to produce a final image that seems authentic to our human vision it turns out that we must essentially simulate what the brain does when we look at subjects with larger dynamic ranges — simply put, we have to make some of the dark stuff lighter and make sure that the bright stuff isn’t so bright that it loses detail.
As with our human vision, it isn’t enough to just make a generic curve adjustment to the whole scene. We generally want to selectively lighten the things that would otherwise be good dark, while controlling the brightness of those that would be too light, all while maintaining tonal relationships among elements in the range in between the extremes.
One solution is to have the dark areas go dark and be intrinsic to the composition as shadows, as in a Rembrandt or a Caravaggio painting. Another solution is not to photograph scenes with such a large lighting ratio. But for some photographers, that may mean giving up too much.
The “Rembrandt/Caraggio” solution can work in some cases, but it is more likely that it won’t because in many cases with photographs (and with paintings more broadly!) things in those dark areas are actually important to the overall image. In fact, if you look at the paintings from those two (and others) and think about what the real world version of the scene would have looked like and what it would have looked like to a camera, you quickly see that they are almost always altering the luminosity relationships among elements of the painting.
In other words, as you wrote, rendering the scene “as… seen by human eyes” and the human visual system.
It is also a matter of individual interpretation. Some photographers’ styles depend on dramatic, higher contrast images and even on flirting with blown highlights and/or black shadows… while others take a different approach and may even mute the highlights and enhance the details in shadows.
To be clear, there ARE some situations in which it is fine, good even, to blow out highlights and block shadows — even though both of those situations are normally approached with a great deal of caution and judgment.
- - -
hasenbein wrote:
That's not a problem of the shadow areas, but only your error in editing. Lowering higlights and raising shadows for the whole image is NOT the correct method. The flatness of the rocks is only because of this flawed method.
Correct method: Have masks for sky, rocks, water; edit exposure, white point, black point, contrast etc. for each mask individually.
Often I tend to agree with your suggested approach, and it is what I most often end up doing. But let’s be a bit cautious about labeling particular approaches as “NOT the correct method” or a “flawed method.”
In fact, a variety of techniques and approaches can be ideal for particular situations. For example, in some cases it can work quite well to do something as simple as lower the “highlights” and raise the “shadows” values, perhaps will increasing contrast to ensure that the midtones don’t get “constipated,” to use a description borrowed from one of my friends. You could also combine this with a simple S-curve to lower contrast at the extremes and add some in the middle.
Is that “the right” approach? Sometimes yes, sometimes no.
The point is that we have a great big bag of tricks that we can call upon to deal with the huge range of challenges presented by different images. No one method is right in all cases, and very few are without value in at least some situations.
- - -
aCuria wrote:
You do have a point, but do note that a standard monitor has less DR than what the eye can see all at once.
The words “at once” are doing a lot of work there, and we need to take a closer look at what that means.
While the human visual system is capable of seeing a huge range of luminosity values — from painfully bright down to the edge of blackness — we can’t actually “see” all of those at once. In order to see at those extremes, our visual system has to do something pretty complicated adjusting and at those range extremes it isn’t instantaneous.
If you were to somehow encounter a real world situation that contained the lowest luminosity levels of that range, which can only be “seen” after minutes of adjustment (and without color!) AND the very brightest that we can see… you would not actually be able to “see” both of those.
Even in a much less extreme situation — for example, looking into dark shadows at twilight while the sky is still rather bright — your “eyes” have to adjust from one subject to the other in order to see them. When you look up at the sky your pulls contract and when you then look into the shadows they dilate, and that change is not quite instant.
The challenge in a photograph, whether printed on paper or displayed on a HDR monitor, is to bring the extremes of that range closer together while maintaining convincing levels of contrast in the middle tones.
Edited on Jun 19, 2026 at 10:22 AM · View previous versions
|
