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Different colour at different zoom levels

Alan Third
I'm just demoing C1 so I don't have much experience with it but I don't think I'm being stupid.

I've got a couple of high ISO (25600) images taken with a D800 that when viewed at fit->50% zoom have a yellow cast to them but beyond 50%, ie. 67%->400%, lose the cast. Processing the files results in a jpeg without the cast, so it looks the same as the zoomed in view in C1.

It seems to be limited to these high ISO shots as I can't see anything changing in any other photo I've looked at.

Any thoughts?

Thanks!
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Comments

13 comments

Date Votes
  • Florin Coter
    Hi,
    Tried a similar situation and did not see any color problem. At any magnification a clean color kept its RGB steady. BUT, what I can think about is noise related issues at the high ISO you used. At different magnifications noise appear somewhat different, hence the color can appear different. It also makes sense the problem to be more acute at low magnification. Jpeg may look "better" because of lost info, i.e. filtering. Hope to have induced some positive thoughts.

    F.
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  • Alan Third
    Thanks for your reply. 😊

    I think it's related to resizing and noise. I had a look at other shots in the 1600-3200 range and they're all fine. I don't have anything between 3200 and 25600 to compare, though. Also it seems to be related to the actual amount of resizing, so vertically shot images vary at different magnification levels to horizontal shots (and maybe screen resolution will make a difference too?).

    Anyway, I thought I'd try to make a demonstration but it doesn't look like as big a change as it does on screen when zooming. I turned off as much noise reduction and sharpening as I could find (the noise reduction makes the colour shift effect stronger).

    http://farm9.staticflickr.com/8185/8148894415_961aed7db8_o.jpg

    Between 50% and 67% the skin tone becomes much pinker and less yellow.

    I think it's something to do with image resizing algorithm when there's a lot of noise. It's not really that big a deal as, like I say, it doesn't happen on shots taken at an ISO setting I'll actually use, but still slightly off-putting.
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  • Florin Coter
    Hi,

    At 100%. I do not think (I am a Physicist, and this about measurement, i.e. Physics) that the noise level allow one to define "a" color for skin or eyebrow. I believe that one MUST know and understand its tools before any expectations bids are made. I also believe that the very high ISO you use is not designed for color reproduction, but for some image salvation... I know this may sound harsh, but that's life.

    On another level, an image has color noise and luminance noise and they behave differently. Try them separately to see which one serve your goals, if at any all.

    Good luck,
    F.
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  • SamC
    I'm glad I'm not the only one experiencing this issue. Please create a support ticket so Phase One is aware that others are experiencing a color shift when viewing images at Fit to Screen. When I talked to support, they were convinced it was my monitor or computer and not a software issue. When I told them it was their software, they stopped responding. I guess they figured it was easier to just ignore one paid customer.
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  • Drew Altdo
    Can you please create a support case and provide us with some RAW files?
    As anything other than 100% is an "interpretation" of the file they are not always perfect. In softwares like Photoshop there are certain zoom levels that will give you "pixellated" diagonal lines rather than clean lines, so nothing is perfect.
    But with some files and some more details we'd be happy to look into this further.
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  • SFA
    [quote="Flxzr" wrote:
    Between 50% and 67% the skin tone becomes much pinker and less yellow.




    The other way around surely? At 100% you should be seeing the direct 1:1 interpretation of the RAW file.

    At anything less (or more) you will be seeing a re-interpretation. Compression of the image as displayed will tend to homogenise things (especially colours) in some way since each reduction in size involves discarding information and very likely modifying other parts to give a result.

    I find I can get away woth relatively high ISO for my newer cameras working from RAW files where the light is good. Definition suffers but colours can be acceptable. Working with files produces in 'poor' lighting conditions (a relative term depending on the subject matter and natural limitations) is always going to be a challenge though, especially at full size.


    Grant
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  • SamC
    There is a definite yellow color cast when viewing the images other than 100% but I have one image where a green dress turns blue at Fit to Screen. C1 is not just adding a yellow tint but also changing one color to another. I sent them screenshots but they stopped replying to my ticket. I can only assume it's because they figured out what went wrong and will fix it in the next update.
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  • Drew Altdo
    Hey Sam,
    Your ticket is very much alive and well.
    The supporter that was working with you is currently out of town on a training assignment and the case was passed along to another supporter who hasn't had a chance to reply yet. I'll give them a nudge.
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  • Alan Third
    Just thought I'd say I'm uploading the raw file that's being particularly awkward as an attachment to a support call just now.

    Thanks. 😊
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  • SamC
    I just tried 7.0.1 and it looks like they failed to fix the issue. I tried recreating the preview and reopening C1 and I still get very yellow/greenish skin at "Fit to Screen" and perfect skin tone at 100%. At this point, I give up. Support sent me a message saying they pretty much figured it out weeks ago but I guess what they figured out was they can't fix it. Back to Lightroom for me.
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  • SamC
    Support finally contacted me after I asked what happened with the fix. According to support, there are many issues that still remain that haven't gone into the 7.0.1 release. A C1 support rep in the Mac forum stated that the 7.0.1 release addressed ALL issues except the ones that relied on the Canon SDK. There seems to be a communication breakdown with C1 with their support reps. I'm guessing 7.0.1 was an emergency release to address the severe bugs and a 7.0.2 will be released within a week or so to address the other issues. I can only hope that I don't have to wait more than a few weeks to fix what I consider a severe bug, one that I reported a month ago. I still don't understand why the Test Department didn't implement the fix with 7.0.1 when they've already figured it out. But then again, I'm still surprised C1 would have released 7.0 as it was and still is.
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  • SamC
    In case anyone cares, I just wanted to follow up and say that 7.0.2 doesn't fix the issue. C1 is aware of how to fix it but they said that it's not a high priority. If anyone is experiencing this issue, I suggest you create a support ticket. If enough people complain, perhaps they'll give it a higher priority and add the fix to next update.
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  • JohnLooy
    Hi, I just noticed this problem myself. 25600 on EM5 with 75mmf1.8. It makes it very hard to process images when output files differ drastically with fit to screen in CO. Would be nice to see this fixed in future release.
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