Someone was discussing to buy Hasselblad X1D or Fujifilm GFX. One of the comments was:
'The X1D cameras just have a different look. It might be the massive color information that the camera is said to have in its firmware. It might be something in the way a "raw" file is generated. It might be the treatment of colors in the camera profile that Phocus has or that Adobe obtained from Hasselblad for Lightroom. Maybe one can wrestle an X1D raw file to look like a Fuji GFX file, but if you just start on the X1D raw in Phocus or even Lightroom, you typically have something of the camera "look" in most shots when you are done.'
That is a quite definitive statement. But do have cameras different color?
So, I downloaded DPReviews studio test images for both the X1D and the GFX 100, generated DCP Profiles for both with LumaRiver Profile Designer developed the Studio Test image with consistent exposure in Lightroom and analysed the ColorChecker colors using Babelcolor 'PatchTool'.
The color differences where like this:
So, it seems both cameras are capable of producing exactly the same color.
on this chart...
That is true.
But, it is a decent indication that the sensors can produce same colors.
If my understanding is right, you used the same chart for profiling. Is so, this makes things even worse. The result you see has nothing to do with the sensors; it produces similar colors because this is what the software was designed to do, having a cheat sheet. They could have written the code so that you would get those colors from a B&W sensor as well.
If producing the same colors was so simple, Adobe would have done it, right, in one of their profiles instead of
this?
Hi,
Yes and no. One thing is that I have actually made a large set of tests.
But, the page you refer to has three fundamental errors:
- The first is that photographs of skin color at best provide a metameric match. A combination of dyes that provide similar stimulus to the skin tones, but don't have a spectral match.
That is one of my points about the test you did. Those color patches are made of dyes spanning a very low dimensional space; it has been discussed here. I never said that those portraits represent color differences when shooting real people; I just pointed them out as examples of color differences.
That was discussed to some extent when Fujifilm owners compared the GFX 50S and the GFX 50S. Color rendition was very different on the portrait prints. The GFX 50S was tested with the 63 mm and the GFX 50R was tested with 120 mm. That makes a difference in shooting distance and moves specular reflections.
DPReview found out that the prints were fading and replaced them. They didn't find a good solution for that.
- The second is that DPReview has found out that they portrait prints are subject to significant fading. So, they change between shooting occasions.
Does the color chart change as well? You can see similar differenced
there. Same for the
color wheel.
As I noted, I used profiles generated the same way. DPReviews uses profiles that Adobe generated.
- The third is that I presume that they are glossy and subject to glare, depending on positioning of the camera and lights.
That can hardly explain the same effects elsewhere, see above. And even if it could, it would cast a deep shadow on your experiment based on the same images.
No, it would not. As the only comparison I made is on the ColorChecker. Here, I don't know how much fading it has. I would recall XRite suggests replacing it after two years.
A way to improve my comparison would be to use the normal ColorChecker as a 'learning set' and use another reference as 'evaluation set'. Such an evaluation set could be ColorChecker GS.
The other references should be an year worth of shooting in various conditions.
You cannot do any controlled experiments under various conditions.
What I have seen here was that my samples from the ColorChecker were essentially indentical. So, all the math and experimental conditions resulted in similar images from the both X1D and GFX.
That doesn't mean that they reproduce the ColorChecker perfectly:
This is a straight screen capture, so it distorts colors a bit.
Comparing the GFX100 with the reference values we have a CIEDE 2000 difference of 2.77 on average 6.04 max.
But comparing the X1D and the GFX 100, the figures are average 0.82 and max 1.6.
So the conversions between the GFX 100 and the X1D are very close.
Now, would we compare the GFX 100 to say the Phase One IQ3100MP, that probably has a different CFA design, the results would be different, although using the same methods:
On the left: Fuji GFX 100 compared Phase One IQ3100MP, on the right Fuji GFX 100 compared to Hasselblad X1D.
Hasselblad's Phocus has a reproduction setting and can calibrate using the ColorChecker.
Left here is Hasselblad Repro setting with Phocus's built on profile compared to ColorChecker reference data. Right is Phocus Repro, calibrated from the test target.
Delta E values are average 2.7 and max 6.38 on the left, with 1.18 and 1.98 on the right.
Is that a camera based difference or is the ColorChecker DPReview uses faded?
We can compare Phocus repro setting with their default rendition 'Factory' and see how much color the 'factory' setting adds.
Quite a lot. The change between reproduction and 'Fcatory' setting is 3.85 DE 2000 on average and 6.79 at most. Much of that is the tone curve, but I guess it is also a lot of color rendition intent.
Let's finally compare the Factory rendition from Phocus with the rendition we got Lightroom using Lumariver:
The differences here are quite significant. That pretty much indicates much of the color difference is coming from Phocus.
Thats all from me for now, going on a photo trip for a week...
Best regards
Erik
--
Erik Kaffehr
Website:
http://echophoto.dnsalias.net
Magic uses to disappear in controlled experiments…
Gallery:
http://echophoto.smugmug.com
Articles:
http://echophoto.dnsalias.net/ekr/index.php/photoarticles
.