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M9 range (not necessarily "dynamic")


adan

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Just playing around with how far the M9 can retain detail at the extremes of exposure. This is not officially "dynamic range", and even if it is a fair approximation, it does not neccessarily compare directly to other methodologies. So don't get too excited - it shows what the M9 does, but not in relation to the M8 or other cameras unless someone tests them the exact same way.

 

Methodology: shoot bracketed exposures of a gray card on white and black background and see how far into over and underexposure the card is still distinguishable from white or black.

 

M9, 21 Elmarit pre-ASPH, ISO 160, "best" exposure 1/180 @ f/2.8, total range bracketed 1/4000 @ f/5.6 to 1/8 @ f/2.8, in half-stops. "Visible range" evaluated on an iMac 24-bit monitor set to gamma 2.2, D5000.

 

My evaluation:

 

8-1/3 stops of native monochrome visual range (ignoring color clipping, and no "heroics" to recover the highlights/shadows.)

 

8 stops to avoid clipping colors

 

7 stops (probably) for printable separation of the gray from the black at the dark end

 

7-1/2 stops printable with "heroic" (and noisy) shadow recovery, but no highlight color clipping

 

7-1/3 stops for printable monochrome separation at both ends

 

8-1/3 to 9-1/3 stops with "heroic" highlight and shadow recovery techniques, for monochrome only

 

For the record, in the darkest exposures, the measured tonal values for the gray card vs the "black" background are:

 

last visible: gray card, 14; black area, 4

not visible but recoverable: gray card 7, black area, 0 (i.e., that's about an ISO 12,000 exposure in the last column)

 

As I said, it would be bad to formally try to compare this to other techniques - but informally, it is interesting to note that this tracks rather well with dpreview's original M8 test, which recorded 8.4 stops of monochrome DR (with some color clipping). I'll be interested to see what their "real" M9 figures are.

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It is interesting to note that Leica could have squeezed in a "pull 40" ISO setting (2 stops over base ISO 160), but it would have been on the bleeding edge - zero margin left for overexposures.

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Adan. Whilst I haven't conducted any precise tests (with my M8) I have been shooting high contrast subject matter recently and am constantly surprised at just how much recovery and fill light the M8 files will take - so your tests on the M9 interest me. I find that compared to my dSLR files, those from the M8 appear able to recover 'smoother' data in highlight areas and fill with substantially less banding problems (at least at low ISO). My 'tests' are real world though and subjective rather than really objective.

 

I do wonder if the recovery is interpreting non-linear data some of which may be spurious, which is why it is excluded from dynamic range claims?

 

Lars, I had trouble getting hold of Kodak greyscales and colour patches when I last tried a few years ago - I was also told that they have a 'shelf life' as they are subject to a degree of 'fading or colour shift' over the years - how true this is I am uncertain but it is worth being aware of at least. I eventually settled on a Macbeth chart as Adan has used.

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Actually, dpreview uses a Stouffer transmission step wedge (needs to be used on a light box, but gives a longer brightness range than a reflective gray scale): Leica M8 Review: 14. Photographic tests: Digital Photography Review

 

Mostly I didn't count the shadow recovery patch because it is pretty ugly. I just wanted to show that there really was still separation there, even if it wasn't visible to the eye without manipulation.

 

As a side note, I'd point out that the M9's LCD screen has had the contrast cranked 'way up compared to the M8. Probably to improve "visibility" in sunlight. But it is completely hopeless for judging exposure or DR, even more than most camera displays.

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