Photographic Dynamic Range (PDR) is a More Useful Measure than the DxOMark Landscape Score

Started Apr 17, 2015 | Discussions thread
OP bclaff Veteran Member • Posts: 8,691
Re: Clarification - Read Noise and Engineering Dynamic Range

Detail Man wrote:

The last time that I recorded dark-frame RAW images on my Panasonic DMC-GH2. As no light was allowed to illuminate the image-sensor, it seems that there might as well have been no lens attached.

In general black frames are unaffected by the attached lens.
There are exceptions because of raw data manipulations due to lens distortion corrections and vignette corections done on some cameras to the raw data.
But even in those cases I suspect only the stacked FPN frames are affected and any effect on read noise is not measurable.

It seems that the (actual) amount of image-sensor illumination that exists in the test-shots relied upon due to lens-flare - even if those amounts by your estimation appear to be comparable in the case of the use of different lens-system on the same camera body - is not a known quantity (and thus the SNR that the image-sensors have operated at is also an unknown) ? More "real world" ?

All I can say is that for PDR the illumination need not be calibrated in any way; since I'm gathering SNR values, it is "self correcting".

Overall Image Quality (IQ) is obviously not dependent solely on dynamic range.
I suspect differences in IQ between lenses has more to do with several other factors than some (possibly immeasurable) difference in dynamic range (which we are carefully trying not to confuse with contrast).


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