IQ180 with Phase One DF camera-colour issue

[Guy Mancuso]

This is the IQ 160 noise test I did a week ago under tungsten light and WB off the second white patch up and I also see nothing off here as it represents my bathroom and the passport card about right on the money and yes my cabinets are that color. ISO 50

and a crop

So i am a little baffled here.

 

[dougpeterson]

I likewise have not noticed out-of-ordinary reds on the IQ180s coming through for testing/eval/demo. But I'm open to the possibility that there is a lurking variable not yet identified.

Phase's color guy is one of the best I know, so I'm sure if there is something there it will be ID'd and compensated for pretty quick.

 

[GeoffRoss]

Okay, here are some more examples taken yesterday morning, which clearly show what I am talking about. These results were exactly duplicated on 3 different backs, and show the same thing on three different computers, all using the latest Capture One software. I think you'll all agree, there IS a problem here.

Regards,
Geoff

 

[GeoffRoss]

I should have also mentioned about these images just posted that the relative image on the left is straight out of the camera and into Capture One , with the only change being the usual sharpening. The two relative images on the right have been corrected for the brick red tones and just a slight bump in the shadows to make them as close to the original colour as possible. My dealer is very expertise in the operation of Capture One, and he went through all the variables on his computer, and yet had to concede that there is an issue in the rendering of the brick red tones by Capture One

Regards,
Geoff

 

[Shashin]

With your last set of images, you could be simply seeing the change in contrast. The "out of the camera" images have more contrast. Contrast naturally impacts saturation. You may simply be compensating for the camera contrast.

 

[GeoffRoss]

Sorry, but that isn't the explanation. I could post here examples with a zero change apart from the corrected colour, and you'll still see the same sort of saturation problem. The reason for the slight, and it is slight, change in shadow is to show the scenes as close as possible to natural as I could. The saturation problem is not subtle. If it was, I never would have even mentioned this problem, but as you can see this really is an unacceptable increase in saturation within these red tones.

Regards,
Geoff

 

[GeoffRoss]

Jack or Guy,

Just a thought, would you like me to upload one of the RAW files so that you can play around with it yourselves.

Regards,
Geoff

 

[Guy Mancuso]

You know that is a good idea actually. Love to see if it is doing it on my machine or in c1 that matches yours. Maybe we can narrow it down to some kind of solution. Something just looks off on your results . I know it would help me ID it better.

 

[GeoffRoss]

Guy, please let me know if you have a mechanism within this site to load the RAW file to, or do you want me to send a link to the likes of yousendit directly to your email address.

Regards,
Geoff

 

[Jack]

Jack or Guy,

Just a thought, would you like me to upload one of the RAW files so that you can play around with it yourselves.

Regards,
Geoff

Please do!

PM me a yousendit, dropbox or mobileme link.

How are you converting these for web view?

 

[Graham Mitchell]

wetransfer.com offers free 2GB file sharing - useful for files larger than 100MB which many other services don't support

 

[Shashin]

Sorry, but that isn't the explanation. I could post here examples with a zero change apart from the corrected colour, and you'll still see the same sort of saturation problem. The reason for the slight, and it is slight, change in shadow is to show the scenes as close as possible to natural as I could. The saturation problem is not subtle. If it was, I never would have even mentioned this problem, but as you can see this really is an unacceptable increase in saturation within these red tones.

Regards,
Geoff

And the corresponding change in the highlights? Sorry, with your last two examples, the contrast difference is enough to change the saturation and by the degree you are showing.

Perhaps you can come up with better examples.

 

[Guy Mancuso]

Yousendit works fine

 

[Guy Mancuso]

Try something for me on your daylight shots drop down to 4900 Kelvin . What temp is it coming in

 

[Jack]

Not received any raw yet, but thought of one other thing to try --- go into prefs and turn off open cl. I would begin a new session and re-import as well to clear all previous cache and settings for each image.

 

[Jack]

Jack,

As a newbie to Capture One and the Phase One IQ180, I've been following this thread with great interest. I'm curious why you suggest turning off OpenCL. Is that something you suggest in general, or is it a suggestion in this case to remove one of the variables in the color management chain? Inquiring minds want to know.

Joe

Hi Joe,

It is a system -- actually video card interacting with the system -- dependent option, and on some machines it improves performance measurably with no ill effects; on others it can create all sorts of weird anomalies and/or actually slow performance. So that's why I recommend turning it off here and trying it.

I am convinced that Geoff's images are not getting properly tagged with the profile.

 

[GeoffRoss]

Sorry about this, but I hadn't realized this had all gone to a new page (2), and it looked like nobody had responded to my last posting. I did warn you that this was my first experience on this website!

Anyway, back the topic in hand, Jack & Guy will you please forward your emails addresses to [email protected], and I will send over one of the RAW files to you.

Regards,
Geoff

 

[Jack]

Hi Geoff:

I got your link and quickly processed the image on my laptop. Bottom line is I think your original is about 1/2 to 2/3rds stop under-exposed, and that's all that's causing the red over-saturation you are seeing. Here is your file processed with outdoor DL profile and as a 16-bit tiff, WB'd off the gray pavement under the bricks which was very close to my normal WB, and then I saturation left at zero which I would normally bump about 3 points. Even with a 1/2 stop bump in exposure, I needed to add about 15 points to the shadow slider, so it could be as much as 2/3rds under -- histo remained good at +2/3rds, FWIW. I then downsized and converted to a jpeg in CS5 for this result:

Here it is with a +1 stop exposure bump, +4 sat, and shadow slider back to 0, all else the same. Histo looked fine even at +1 -- image still looks okay to me though a bit hot, but again I am on my laptop:

 

[GeoffRoss]

Hello all,

I just thought I would enlighten you about the final results of the saturation issue.

Jack Flesher has been very helpful indeed. I sent a few RAW files directly to him to examine on his computer, and the result is that there is two sides to the problem. One is that my camera was underexposing slightly, which of course increases colour depth, but there also is a saturation issue, and more so with the orange-red tones. Both these things we have agreed upon, but what doesn't make sense is why we have had 3 different backs have the same issue, and Jack has not reported any such issue with the backs he has used.

My dealer has sent some sample images to Phase One for assessment, but I haven't heard any results yet. My solution (thanks to Jack) has been to modify in Capture One's colour editor a camera profile to fix the problem, which I now use. So yes the issue has been got around, but it would be nice to know the real cause.

Again, thanks Jack for your assistance!

Regards,
Geoff Ross

 

[Jack]

Geoff,

We should add that the one constant between the three backs you tried were you used the same body and lens. My initial suspicion is that there are three separate issues possibly contributing:

1) Slight body under-exposure, on average about 1/2 stop;

2) Possible lens-cast and/or lens induced contrast issue;

3) It is winter and overcast/raining in Geoff's half of the world right now, and wet and overcast both can increase relative saturation.