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

Started 11 months ago | Discussions
DimLS
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D700 vs Df: same exposure settings but 0.9 stops file exposure difference
11 months ago

I noticed smthg strange today, as i took an indoor test shoot:

D700, Ultron 40mm, ISO 6400, 1/60, f8, RAW

Df, Same Ultron 40mm, ISO 6400, 1/60, f8, RAW

And the Df file is 0.9 stops more dimm than the d700 file.

What do you think about it?

  • Moreover, when both files are made to have the same brightness curne in ACR, the noise is the same
  • Moreover, on DXO, D700 and DF have the same values for color sensitivity, noise for e.g. ISO 200,400,800,1600...as if the sensor of Df is not better in the noise, color sensitivity department, which is exactly what i saw with the test shot. 

What do you think about it?

Nikon D700 Nikon Df
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Craig
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 11 months ago

Not sure what the problem is but if that is true I am liking my D700 more and more and will probably hold on to it longer still.

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olakiril2
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 11 months ago

It is common for the actual ISO sensitivity to be different than the manufacture ISO. Strange thing is that DXOmark for the 6400 reports the same for Df/D700. I guess there is more variability from camera to camera.

0.9 is kind of alot though did you match their histograms?

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David314
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like to see raw histograms
In reply to DimLS, 11 months ago

DimLS wrote:

I noticed smthg strange today, as i took an indoor test shoot:

D700, Ultron 40mm, ISO 6400, 1/60, f8, RAW

Df, Same Ultron 40mm, ISO 6400, 1/60, f8, RAW

And the Df file is 0.9 stops more dimm than the d700 file.

What do you think about it?

  • Moreover, when both files are made to have the same brightness curne in ACR, the noise is the same
  • Moreover, on DXO, D700 and DF have the same values for color sensitivity, noise for e.g. ISO 200,400,800,1600...as if the sensor of Df is not better in the noise, color sensitivity department, which is exactly what i saw with the test shot.

What do you think about it?

That sounds like a lot,

I would want to see the raw histograms using rawdigger

dxomark shows an advantage in noise color sensitivity etc.

and shows the Df as having a slightly greater measured ISO vice the D700 at the same setting

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JF69
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Can you upload raw files?
In reply to DimLS, 11 months ago

Maybe the likes of Iliah Borg or bobn2 could chime in as well.

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Horshack
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Check the aperture lever on your D700
In reply to DimLS, 11 months ago

The Nikon F-Mount controls the aperture on lenses via a mechanical lever that couples to a slider on the lens. The tolerances for the F-Mount lever are pretty exacting and if the lever gets bent (not that unusual) then the indicated aperture will no longer match the actual lens aperture. Most of the time a bent aperture will cause the lens to fail to stop down rather than stopping down too much, which means if it is the lever it's likely the one on your D700 that is bent/out-of-spec since it's producing +.9EV brighter exposures than your Df.

There are a few easy ways to check the calibration of the lever. The first is to shoot both bodies wide-open and see if the exposure matches, since the coupling doesn't have to stop the lens down for wide-open apertures. Another way is to take each body and shoot wide-open and then stopped down 1EV (f/2.8 -> f/4 in your case) at the same shutter speed/ISO - the exposure of the f/4 image should be -1EV the f/2.8, and more importantly you should see the DOF difference (shoot a subject near MFD to make the DOF difference more noticeable); if not then the lever is not stopping down appropriately.

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Horshack
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Re: Check the aperture lever on your D700
In reply to Horshack, 11 months ago

Btw, since the Ultron also has a manual aperture dial another way to test the lever's calibration is to use the manual aperture dial instead.

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Radu Grozescu
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Re: Check the aperture lever on your D700
In reply to Horshack, 11 months ago

Horshack wrote:

Btw, since the Ultron also has a manual aperture dial another way to test the lever's calibration is to use the manual aperture dial instead.

Or to use any lens (including G type) at maximum aperture.

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Marianne Oelund
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Aperture Control
In reply to DimLS, 11 months ago

DimLS wrote:

I noticed smthg strange today, as i took an indoor test shoot:

D700, Ultron 40mm, ISO 6400, 1/60, f8, RAW

Df, Same Ultron 40mm, ISO 6400, 1/60, f8, RAW

And the Df file is 0.9 stops more dimm than the d700 file.

What do you think about it?

I agree with Horshack that the most likely explanation is aperture-control discrepancies.  Try the test again using the lens' aperture ring (set Custom Settings -> f9 (or f7 on Df) Aperture Setting to "Aperture ring"), and see if the exposures come out more similar.

Alternatively, using command-dial control of aperture, select the aperture that is 2 stops down from wide open, press the Preview button, and see if the diaphragm (viewed through the front of the lens) stops down to exactly half-diameter on both cameras, as it should.  Use a second camera to photograph the diaphragm if you want an accurate measurement.

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Frank C.
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to Craig, 11 months ago

nothing wrong with the d700, really... nothing.

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StillLearning
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 11 months ago

My D700 was .7+ over exposure outdoors.  I set -.7 when shooting outdoors but 0 comp for indoors.  I don't mind a little brighter for indoors.

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Iliah Borg
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 11 months ago

If you are checking with ACR or LR, D700 and Df have different baseline exposure compensation too. Current for D700 is 0.5 stops, for Df - 0.25 stops. They may be using different curves too. So, apart from the possible change in light and aperture lever bent, it might be processing.

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chooflaki
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 11 months ago

Do you have the Df set to to Non CPU lens data 43mm, F2 for the Ultron?

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DimLS
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to Iliah Borg, 11 months ago

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.

If D700 exposure is the benchmark, i guess i should over expose the Df. If the Df is the benchmark, i should under expose the D700.

May be i should get out on a bright day ( i live in south Europe) and shot a grey card and see the histograms. Or may be i should use the sunny f16 rule and see in which camera its working better.

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Horshack
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 11 months ago

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

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DimLS
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to Horshack, 11 months ago

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!

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Radu Grozescu
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 11 months ago

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!

There may be 2 aspects:

- real ISO of the cameras and

- the way the exposure meter works.

The third variable may be the processing in camera (picture control).

You can use a white piece of paper and fill the viewfinder to eliminate the measuring pattern.

Use the 50/1.8 at 1.8 (so you will have the same the real aperture value).

Use the same Picture control, measuring pattern and white balance (non Auto) on both cameras. Very important, because both Picture control and White balance have a visible effect on the luminosity of the image, so put them the same on camera, do not adjust them in software.

Now, if you shoot in Manual mode, same ISO (non Auto) same shutter speed and same aperture (1.8) on both cameras you will see the ISO difference.

If you shoot in A (aperture priority), same ISO (non Auto) and same aperture (1.8) on both cameras you will see the metering + ISO differences.

You can measure the tones in the image using Nikon View (or PS or other tools, including the histogram).

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bigconig
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to StillLearning, 11 months ago

StillLearning wrote:

My D700 was .7+ over exposure outdoors. I set -.7 when shooting outdoors but 0 comp for indoors. I don't mind a little brighter for indoors.

Me too. I always considered -.7 to be 0 on my 700

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rhlpetrus
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 11 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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Iliah Borg
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Re: D700 vs Df: same exposure settings but 0.9 stops file exposure difference
In reply to DimLS, 11 months ago

I do not understand what is baseline exposure compensation.

When you open the raw file in ACR it adds some exposure compensation behind the scenes. The slider is at zero, and you do not see it. In case of D700 half a stop is added, in case of Df - 0.25 of a stop. The difference between brightening is those 0.25 of a stop you observed in your last experiment.

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