D700 vs Df: same exposure settings but 0.9 stops file exposure difference

Started 4 months ago | Discussions thread
rhlpetrus
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 4 months ago

DimLS wrote:

Horshack wrote:

DimLS wrote:

Thank you very much for your answers

Actually, i had set the Df with aperture ring setting, and d700 with dial setting. So after Horshack's comment, i redid the test using the aperture ring only. I also used Nikon 50mm f1.8 G (from the Df kit) on both cameras. I did an indoor test in ISO6400 and 200.

Results:

There is a much smaller difference in what i see in ACR latest version, of about 0.25 stops (not scientificly measured) in all sets of photos on both cameras with both lenses: D700 files were about 0.25 stops brighter.

The good thing is that Df looks indeed much cleaner in ISO 6400, even with 0.25 stops increase in ACR, especially in the dark areas of the image.

Another good thing that crossed my mind, is that the light meter tested in spot setting, makes exactly the same measurements on both cams. Its just the file exposure different.

Borg thanks. I do not understand what is baseline exposure compensation. Do you mean the fine tune optimal exposure in the menus? I guess not.

Anyway, it seems a bit strange that there is a 0.25 stops difference, except if its how ACR treats both camera's files. May be its a difference in the real ISO values vs the ISO settings value that have a normal difference between the 2 sensors. May be Nikon wanted this way because its easier with the Df to preserve the highlights in shooting conditions because the headroom for the dark is big for the Df.

Glad you got it sorted out. Iliah's comment about base exposure compensation referred to the raw processor (ACR/LR) adding an automatic exposure adjustment to every raw file it processes for a given camera model. I believe this is done to accommodate/offset biases built into the metering system of the camera model (some meter a certain EV away from expected middle grey), but Iliah will be able to explain it better

Yes i got it! Now i finished a quick test with a grey card, indoors with sufficient daylight. I move the card to more and to less lighted areas and it seems from the histograms that the D700 file is a bit overexposed, and the Df is accurate. May be i will redo the same with stronger daylight to see if i get the same results.

So my initial concern is resolved i guess. Df is performing just fine!

Re impression of noise, had you resized Df to 12MP? That shpuld be a better comparison, as if looking at same final sizes.

Re .25 stop difference (which may be just due to converter offset) that's usually not that relevant, since there is actually no "correct" exposure, since it depends on your use of image and PP routine.

One thing is good to know: which is the midtone that each camera uses for the spotmetering? It varies from camera to camera, as Horshack mentioned. Did you measure the light from grey card with the spotmeter or with other mode?

merry Christmas!

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Renato.
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