Can we have too much Dynamic Range?

Started 7 months ago | Discussions thread
alanr0
Senior MemberPosts: 1,261
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Re: Tonality of color neg film?
In reply to jrtrent, 7 months ago

jrtrent wrote:

Lightpath48 wrote:

When my son-in-law bought his Nikon D5100 I immediately saw what looked like "duller" images than those from my D5000. I later found out that his camera's sensor had superior DR, and with a little PP, those images were significantly better. My little Fuji X10's DR400 images tend to look flatter than its DR100 images by quite a bit. But again, they perk up with PP, yet without the clipped highlights of DR100 shooting.

I found this quote interesting:

"Camera manufacturers are faced with a classic tradeoff: contrast versus dynamic range. Most images look best with enhanced contrast, but if contrast is increased, dynamic range suffers. Dynamic range can be increased by decreasing contrast, but images tend to look flat. That won't sell cameras!

One way around this tradeoff is to apply a curve, shown in solid black in Fig. 2. Contrast is reduced in the shadows and highlights, but increased in the important midtone area, which is responsible for perceived contrast." http://www.normankoren.com/digital_tonality.html

The OP had asked, "Can a sensor with a greater DR produce end up producing results that look 'flat' without post processing," but I wonder if the sensor itself makes much difference in what we see or if it's mostly the manufacturer choosing tonal curves that can look pleasant or unpleasant according to one's taste.

I have a feeling the processor is much more important than the sensor.

Got it in one.

To the best of my knowledge, the output of CMOS or CCD sensors used in mainstream digital cameras is linear. Improvements in sensor dynamic range come from reduced noise and by increasing well capacity, so that brighter highlights can be recorded without clipping.

The processor needs to apply a tone curve for a JPEG image to display properly. Typical output devices use something not too far from the sRGB characteristic and will produce horribly contrasty results from a linear input.

So appearance is largely down to the JPEG processing, and particularly to the tone curve and any local contrast adjustments. My preference is for a neutral to flat out-of-camera image which can be modified in post-processing.

I don't see any down-side to a high dynamic range sensor.  If OOC appearance is critical, then choose a camera whose output suits your taste, or with sufficiently flexible processing to suit your needs for a range of subjects and lighting conditions.

The OP refers to Aptina's sensors, presumably MT9V032 or similar models.  As far as I can tell, these achieve wide dynamic range by allowing different exposure in different parts of the frame. They are intended for cost-sensitive video applications, rather than high quality imaging, and the low light performance appears to be rather poorer than in current digital cameras (<25e- read noise specified).

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Alan Robinson

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