Fuji GFX ACR Raw Conversion WB

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Chris Dodkin
MOD Chris Dodkin Forum Pro • Posts: 10,245
Fuji GFX ACR Raw Conversion WB
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It's not often I shoot RAW + JPEG, but when doing so recently I noticed that the 'as shot' WB settings in ACR were way off.

Specifically that they added a significant amount of magenta tint.

In camera JPEG top / ACR JPEG bottom

This isn't a subtle difference, it's way off base.

Upon inspection, this is happening with all images, daylight, studio flash, GFX50S and GFX50R bodies, and looks to be ACR applying a WB profile for the camera which is completely out of whack.

I decided to look into this further - Using my color meter to measure the light's K color temp and CC value at time of capture, to compare with ACRs data.

Top 'as shot' in ACR / Middle 'As Metered K and CC' / Bottom 'Eyedropper' in ACR

I set up a test scene using my Passport Color palette and my neutral grey card target, in full sun, lit at a 45 degree angle.

I tested the GFX50S and R, with the same lens, but got identical results from the two bodies, so only show one test here.

As noted in previous photography, my test scene 'as shot' showed a very high magenta cast, and a CC value of +17. Which not only looks ridiculous, it's way outside of what you'd expect from a daylight shot, unless there was an overriding green tint to the light, say from grass reflection. No grass in this test set-up. If you look at the central 'mid grey' spike in the histogram, you can see the magenta cast in the associated RGB histogram. Instead of being coherent, the red, green and blue peaks are significantly offset from each other.

The 'as metered' values for WB (KCM-3100 Meter), measured from the target position with the sensor facing the camera position were 5000k +3, so the K was the same, but the CC value was way different, and more in line with what you might expect to see. When I set those values in ACR as a 'custom' WB, I see a much better WB result, leaning slightly to green in tint. Reviewing the associated RGB histogram, you can see that the red is offset from the green and blue at that 'mid grey' spike.

Finally, I used the eyedropper tool in ACR to sample the 'neutral' grey card, and also the 'neutral' grey chips on the Passport. This gave a small variation in values, but all were clustered around 5250k +9. This looks the most neutral based on the grey card used in the test, as you might expect. On the associated histogram, the 'mid grey' RGB peaks now align.

So I concluded that ACR was adding Magenta to the image at RAW conversion, for no good reason, and appeared to be doing this universally - probably with a bad/incorrect camera profile.

I tried the same sample test, imported into C1, to see what I got there.

Completely different values for 'as shot' WB! 5296k -0.5

I used the eyedropper in C1 to sample the 'neutral' grey target

Different values again! C1 showed 'sampled' WB to be 5547k -2.3

These values were way different from ACR, and way outside of what I'd expect from daylight, and were at complete odds with my metered values. C1 appears to just be making sh!t up at this point, it's not even close to reality.

As an additional test, I tried dialing-in my metered K value into the in-camera WB, shooting the test scene, and then importing that RAW file into ACR. It's possible to input the K value as a Degrees K WB, but not the CC value.

On review, the K value 'as shot' in ACR did not match the value I'd set in camera! So it appears that ACR is also just making that number up, and is not reading it from any metadata in the RAW file. Or, if it is reading it, it's reading it incorrectly. The camera does not allow the metered CC value to be used for K WB, so the area I'm having the most issue with is not covered by this method of in-camera WB setting.

So where I'm at right now is - well pretty much where I started.

I can see that the RAW files in ACR have too much magenta. +CC values.

I can meter the light at time of shot and get K and CC values.

I can dial the K value into the GFX and it will be changed by ACR. I have no way of accurately dialing in a CC value into the GFX, changing the WB tint in the camera effects the JPEG but appears to be ignored by ACR.

I can use the metered WB values in post to get a more accurate WB than ACR is providing, and then fine tune from there.

I could use the 'preset' WB options like 'Daylight' in ACR which assumes 'Daylight' is 5500k +10, but this often looks too warm.

I could shoot a grey card for every location/set and use in-camera custom WB or ACR eyedropper WB in post.

For now, I've built a custom profile in my color meter to get me to where I think WB should be. I can meter each shot/set and record those values to use later in post.

I'd rather have Adobe fix the GFX profile(s) so that it's (more) accurate, and has some correlation to the GFX camera WB settings. If Fuji can get it right in-camera, surely Adobe can get it right in post!

What's everyone else seeing with their GFX RAW file WB?

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Your time is limited, so don't waste it arguing about camera features - go out and capture memories - Oh, and size does matter - shoot MF

 Chris Dodkin's gear list:Chris Dodkin's gear list
Fujifilm FinePix X100 Fujifilm X100F Canon EOS-1D Canon EOS-1D Mark II Fujifilm X-Pro1 +41 more
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