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Thread: IQ180 with Phase One DF camera-colour issue

  1. #51
    Sr. Administrator Jack's Avatar
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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by GeoffRoss View Post
    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?
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  2. #52
    Senior Member Graham Mitchell's Avatar
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    Re: IQ180 with Phase One DF camera-colour issue

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

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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by GeoffRoss View Post
    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.

  4. #54
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    Re: IQ180 with Phase One DF camera-colour issue

    Yousendit works fine
    Photography is all about experimentation and without it you will never learn art.

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    Re: IQ180 with Phase One DF camera-colour issue

    Try something for me on your daylight shots drop down to 4900 Kelvin . What temp is it coming in
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    Sr. Administrator Jack's Avatar
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    Re: IQ180 with Phase One DF camera-colour issue

    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.
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    Senior Member Joe Colson's Avatar
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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by Jack Flesher View Post
    go into prefs and turn off open cl
    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.

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    Sr. Administrator Jack's Avatar
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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by Joe Colson View Post
    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.
    Jack
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  9. #59
    GeoffRoss
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    Re: IQ180 with Phase One DF camera-colour issue

    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

  10. #60
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    Re: IQ180 with Phase One DF camera-colour issue

    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:

    Jack
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  11. #61
    GeoffRoss
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    Re: IQ180 with Phase One DF camera-colour issue

    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

  12. #62
    Sr. Administrator Jack's Avatar
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    Re: IQ180 with Phase One DF camera-colour issue

    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.
    Jack
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    Re: IQ180 with Phase One DF camera-colour issue

    Jack, I still think there is something for Phase to investigate in the proportional red rise with underexposure. Certainly, all sats rise under those conditions but red rises more than green or blue. I see similar effects with low sun angles of course (different in Los Altos and Melbourne?). Not much to be done as flux dependent balance of the primaries is a fundamental sensor property. However, a red-reduce C1 style might be handy.

    I don't have a quantum efficiency chart of the Dalsa chip but I would suspect its red response is extended relative to green/blue and to our eyes. So when all primary fluxes are low or when red light is prevalent (low sun eg), the camera sees more of it than we do visually. Wonder who has the chip response data?

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    Re: IQ180 with Phase One DF camera-colour issue

    Forgive me for off topic but

    does your IQ comes with the plastic thingie that cover the cable release etc (below IQ180 sign). Mine does not and my dealer told me that Phase One sent the back without it.

    Thanks

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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by Dan Santoso View Post
    Forgive me for off topic but

    does your IQ comes with the plastic thingie that cover the cable release etc (below IQ180 sign). Mine does not and my dealer told me that Phase One sent the back without it.

    Thanks
    Mine came with the rubber piece that covers it. My dealer is going to order replacements (as I know mine will be lost in short order) but the extras aren't available yet.

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    Senior Member kdphotography's Avatar
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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by Dan Santoso View Post
    Forgive me for off topic but

    does your IQ comes with the plastic thingie that cover the cable release etc (below IQ180 sign). Mine does not and my dealer told me that Phase One sent the back without it.

    Thanks
    Small self-sealing plastic door (lack of a better term) is on the front of the back below the lcd; A rectangular rubber gasket covers the side ports next to the CF card door. It's included. You should be able to get a replacement from your dealer...

    ken

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    Re: IQ180 with Phase One DF camera-colour issue

    For some reason all IQ sent to my dealer does not have the rubber gasket.

    what in the world!!!!

  18. #68
    Subscriber Member tashley's Avatar
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    Re: IQ180 with Phase One DF camera-colour issue

    Like Terry says, you'll lose it in moments. Whenever I peel the top half off to stick the tech cam shutter sync thingie in, it is a bugger to get back in afterwards. I anticipate getting through a few of these.

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    Re: IQ180 with Phase One DF camera-colour issue

    Geoff i got your file but what lens are you using here . Its marked 75mm. Phase does not have a 75mm lens unless it is the zoom
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    Re: IQ180 with Phase One DF camera-colour issue

    Okay Geoff sent me a file but first you need to understand where the light is coming from which is directly overhead. Here is the problem the brick in the front is really in the shadows and you really can only go by the top of the bricks. Plus the color chart is on the shadow side. Plus you are .5 underexposed right out of the gate. So I boosted the exposure and only go by the top bricks as far as color because the bottom bricks are underexposed and in the next frame I boosted the shadow side.





    Now going in and boosting the shadow side the bottom bricks are still under but not as bad. Honestly this is not a great file . Really the sun should be hitting the whole scene directly not from the top plus it is overcast which causes more saturation. I'm just not convinced given this file.

    Boosted shadow

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    Re: IQ180 with Phase One DF camera-colour issue

    I see where you are coming from, but after shooting in red rock country all weekend, I'm seeing some red saturation issues, and I know it's not underexposure or shadows. Still seeing if I've got something in my workflow that might explain it. but if I want saturation to all colors, I'm having to pull the reds back down sometimes.

    I'll work on in more and get back with you.

    BTW, I understand about it being underexposed maybe contributing to this, but isn't this "new"? I don't recall issues like this with the p65+, and I know reichmann and dubovoy both mentioned some red issues.
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  22. #72
    GeoffRoss
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    Re: IQ180 with Phase One DF camera-colour issue

    Guy,

    Sorry about the delay in responding, but I haven't had much time lately.

    I can send to you an identically positioned Canon image of the same subject matter, and I can assure you the Canon doesn't have the same reds saturation problem, also being opened in Capture One using a generic Canon profile.

    Anyway, I know there is a problem, and I have taken steps to solve it, by utilizing a modified camera profile. So as far as I am concerned I have done my best to alert others to it, and each person can make their own judgement. If you are happy with what you are seeing for your own images, then that's great, but I wasn't.

    It is interesting that it appears that Wayne has also identified the same thing.

    One other thing that occurred to me was that maybe others aren't viewing on a full gamut monitor. I use a top of the range Eizo, which pretty well covers the full Adobe RGB gamut. So it is possible that the issue isn't so obvious for others who have monitors with a more restricted colour gamut. It would explain it.

    Regards,
    Geoff Ross

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    Re: IQ180 with Phase One DF camera-colour issue

    I did a quick test via IQ LCD, did some bracket with red clothes, and I found the color in the LCD is darker/more saturated than the actual clothes even when I overexposed it.

    I will check more in my PC later. This may be because of inaccurate LCD coloring.

    During my last studio shoot, I notice that overexpose image gives washout color in the skin (LCD), while tethered the color looks nice in my monitor. I suspect the LCD's color is inaccurate.


    Best,
    Dan

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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by GeoffRoss View Post
    One other thing that occurred to me was that maybe others aren't viewing on a full gamut monitor. I use a top of the range Eizo, which pretty well covers the full Adobe RGB gamut. So it is possible that the issue isn't so obvious for others who have monitors with a more restricted colour gamut. It would explain it.

    Regards,
    Geoff Ross
    Actually, it wouldn't. The relative difference would still be preserved in the conversion. As others have pointed out, there is certainly a contrast problem impacting your saturation.

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    Administrator, Instructor Guy Mancuso's Avatar
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    Re: IQ180 with Phase One DF camera-colour issue

    I'm on a Nec wide gamut monitor as well as Jack is
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    Re: IQ180 with Phase One DF camera-colour issue

    Does anyone with this back have the facilities to do a proper color check? The testing here is too subjective to pin point the problem. At least a controlled environment would help.

  27. #77
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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by Shashin View Post
    Does anyone with this back have the facilities to do a proper color check? The testing here is too subjective to pin point the problem. At least a controlled environment would help.
    Shooting a color checker and getting exact values is very difficult. That said, I have droppered the direct Sun crop of my Passport I showed earlier in this thread. If in C1 I use a linear response curve and flash profile, then adjust my grays to balanced by making slight adjustments to the levels slider and with saturation at 0, I am actually showing a slight R channel UNDER saturation in the reds and magentas, and a slight over saturation of R in the blues and cyans, with skin-tones being very close. But, we are talking really small amounts to begin with, so for my uses I have to say it is quite excellent as-is.

    YMMV,
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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by cunim View Post
    Geoff, I shot some bricks with my IQ/C1 on the PC. Appears to me that there is no trace of red oversaturation at normal exposure, but that the proportion of red becomes nonlinearly higher with underexposure. The left image is slightly overexposed and looks very like the real thing. Slightly undersaturated if anything. The right image is underexposed by 2 stops and then raised in LR. Note the proportional increase in the red component. I would guess the QE of the chip is higher in the red and this is not being well compensated in C1. Just a guess.
    What happens when you "raise" the exposure is that you steepen the curve. This raises contrast but also significantly increases saturation - in all colour channels. Just look what has happenned to your foliage.
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    Re: IQ180 with Phase One DF camera-colour issue

    Just a thought.....
    You guys who are having this red problem, what firmware version are you running?
    The reason I ask is that the first time I shot with an IQ180 was when I did the demo for the global dealer launch here in Dubai. Those backs we used were pre-prod prototypes and weren't fully profiled. They had a terrible over saturation problem in the mid to three-quarter tone part of the red channel. The shadows were also slightly green.
    My production back does not have this problem at all. We have had a firmware update since we received our backs, so I am curious to know if you are running older firmware. At the very least it would be good to remove that as one of the variables in this discussion. I am running version 1.19 from May26 2011.
    For the record, my IQ180 is not showing any sign of this red over-saturation. Nor is my Aptus 12.
    The accuracy in the Khaki/green area is also better than my P65+.
    Cheers,
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  30. #80
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    Re: IQ180 with Phase One DF camera-colour issue

    Hello all,

    I am attaching two images taken a short time ago, and both within a couple of minutes of each other. Unfortunately it is still raining here, which affects the real colour judgement of things, but in this instance it is more a comparison of colourv rendering between a Canon image, and the Phase One image. Unless people have difficulty distinguishing colours, then I think this example will clearly show what I have been referring to. The images were both processed in Capture One and the only change has been the standard sharpening. The Phase One rendering of the bricks is certainly over-saturated. Even the Canon is more saturated than the actual bricks are.

    I will leave it for you to make your own judgement.

    Regards,
    Geoff Ross

  31. #81
    GeoffRoss
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    Re: IQ180 with Phase One DF camera-colour issue

    Try again! I Forgot to covert to SRGB, sorry.

    Regards,
    Geoff

  32. #82
    GeoffRoss
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    Re: IQ180 with Phase One DF camera-colour issue

    and the Canon image

  33. #83
    GeoffRoss
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    Re: IQ180 with Phase One DF camera-colour issue

    One more time!

  34. #84
    GeoffRoss
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    Re: IQ180 with Phase One DF camera-colour issue

    I don't know what is happening here, I can't get both images to transfer. It all looks correct with both images prior to posting.

    Geoff

  35. #85
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    Re: IQ180 with Phase One DF camera-colour issue

    Geoff, the P1 file you are trying to attach is a tiff, and probably too large.
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    Re: IQ180 with Phase One DF camera-colour issue

    Quote Originally Posted by siebel View Post
    What happens when you "raise" the exposure is that you steepen the curve. This raises contrast but also significantly increases saturation - in all colour channels. Just look what has happenned to your foliage.
    Yes, well put. All the saturations increase with underexposure. However, my point relates to the proportional red saturation. If we consider the total color value at optimal exposure, red is a certain percentage of that. If we underexpose red becomes a larger proportion of the total. At least it does on my IQ180. Try it on yours. Just add up the RGB values and calculate a proportion for each primary.

    Simple exposure correction algorithms do not model this effect so the corrected image keeps the inaccurate red cast. Perhaps this is normal and we are expected to establish our own camera profiles for different lighting conditions? That's fine if the effect is subtle. A few profiles will cover most conditions. If the effect is substantial, however, modeling becomes a more effective way of handling it and that is up to Phase.

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