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Dynamic Range. Highlights -v- Shadows
I am slightly confused and intrigued ................

Whenever, the more experienced photogs on this site (including the Reviewers) discuss Dynamic Range (DR) they always seem to go on and on about highlights..

I get the impression that the Holy Grail seems to be a camera that has a high DR into the highlights..

But therein lays my confusion..

For my experience has been that if I take a pic of say someone wearing a dark grey suit with black stripes/patterning it is often difficult to see a distinct colour separation between the dark grey and the black; the two seeming to merge into one dark hue. Similarly, if I look at a black item where the light is catching it, I can distinctly see what appears to be a lighter region where the light has caught the object and a darker region that hasn't been caught by the light; but trying to capture this gradation of colour on a camera always proves difficult..

I am also of the opinion that by and large highlights/lighter colours are easily distinguished from each other compared to darker colours like dark greys and blues next to black..

So I would have thought that what would be more exciting is a camera that can distinguish between the various darker shades..

I have just read the review of the Fuji S5 Pro and was very impressed by it's DR response in the darker regions..

So am I missing something?.

Can some of you more experienced/knowledgeable photogs explain to me, why all the rage about cams and their DR highlight ability and, what appears to be, very little concern for DR in the darker shadows?..

Comments (5)

Plevyadophy wrote:.

So am I missing something?.

Yes you are. Dynamic range isnt simply about light and dark but about the ability to handle different intensities of light. For example, a white piece of paper is just as white as a bright light. However, the white piece of paper is most likely far less intense than the light. You can look at the paper without trouble but you probably will squint a little when looking directly at the bright light. Thats because the intensity is much greater..

Thats why indoor shots of windows on sunny days are so difficult. The intensity of the light streaming through the window is much greater than the intensity of the indoor light being reflected from the majority of the objects in the room..

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window.

Digital cameras do fairly well at capturing shadow detail. Thats probably why do you dont hear about it as much as you hear about highlights. But rest assured, it's just as important a consideration and it is definitely discussed in relation to dynamic range...

Comment #1

If you've lost your highlights (as in blown out with RGB values 255, 255, 255), there is no data to be recovered. If you have any photography experience, think of shooting transparency film where you expose for the highlights. Exposing for the highlights will usually leave some information in the shadows that can be recovered. That's why it's more important to maintain highlight detail than shadow detail..

Larry Bermanhttp://BermanGraphics.com..

Comment #2

Plevyadophy wrote:.

So am I missing something?.

I think that you are less confused than the other folks are..

For cameras that produce Raw photos, highlight headroom is easily increased simply by underexposing. The metering system on a digital camera is calibrated to produce a certain amount of "highlight headroom" between the midtone point and the sensor max. This is an arbitrary design choice made by the camera manufacturers. They try to choose a midtone reference point that's low enough to provide room for highlights, while not making shadows too noisy..

Another theoretical problem in the shadows is the reduced number of tonal steps, but for today's sensors this seems to be trivial compared with noise. Okay, some of the noise is the direct result of reduced tonal resolution, but again for today's sensors that seems to be trivial compared with other noise sources..

The new Canon 1DmkIII features a "highlight tone priority" mode that works by "expanding the range from the correct exposure level (18% gray) to the maximum allowable highlight level". Canon notes that the tradeoff when using this feature is that "Depending on shooting conditions, noise in the shadow areas may increase slightly." (Quotes from Canon's 1DmkIII White Paper.) Note: the 1DmkIII sensor has two extra bits of tonal resolution (14 vs. 12 for other Canon DSLRs) so that's not an issue here..

So yes, the limitation on dynamic range is actually controlled by shadow rendition...

Comment #3

But if you've lost your shadows (rgb values 0,0,0) there is no data to be recovered either. Which is more important (highlights/shadows) will depend on the picture you are taking. If both are important and the range is more than your camera has available, you can try HDR in some situations...

Comment #4

The Fuji S5 has a special set of secondary sensors that capture the extra dynamic range. I'm not sure if that's as useful as Fuji would like, but it's not useless..

When recovering shadows the biggest problem is that you tend to get more noise in the recovered shadow - because you are amplifying small errors to large ones. When recovering highlights the problem is that you cannot recover the colour accurately. This typically means you end up with a pink sky instead of a blue one in the recovered part, for example. For this reason dynamic range is not always useful..

The technique you need to investigate is "Exposing to the Right"..

Of course you need to shoot RAW and process in 16-bits to exploit these technique well..

StephenG.

Fuji S9600Fuji S5200Fuji F30Fuji E900Canon A710ISPCLinuxOS..

Comment #5


This question was taken from a support group/message board and re-posted here so others can learn from it.

 

 

 

 

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