Thread: UMP FPN/Colored Vertical Lines @ ISO800 Even After Calibration, No Post Lifting?

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  1. #1 UMP FPN/Colored Vertical Lines @ ISO800 Even After Calibration, No Post Lifting? 
    Junior Member
    Join Date
    Feb 2016
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    29
    Hi. Had my UMP since April/May and recently began noticing what may not be the traditional FPN (monochrome vertical lines evenly spaced across the whole image) but more of the blue-ish vertical lines randomly spaced across the whole image. Like someone dipped a comb with random missing teeth in blue paint and ran it down my entire frame from top to bottom -- if we want to get creative about it. Can't post any stills right at the moment but I will, and of course I am planning to contact BMD about it but I thought I'd float this out there as I prepare some samples and see if anyone else has dealt with this. What alarms me is that I am seeing this in images shot at 800 ISO without any lifting in post, and shots that were taken following a calibration where I left the camera on for 10 minutes prior. The range of the image it appears in is also alarming - not just the darkest shadows, but dark-colored objects that are otherwise well-lit. Like a dark shirt a subject is wearing that is being directly hit by the key light. In these cases you may not see it in a still (I will be uploading short clips as well for this reason) but motion really gives it away. It's like you're looking at his shirt through prison bars.

    I've run some tests with the body cap where I run signal to my 40" LCD via SDI-HDMI converter and do indeed get cleaner results after running it for a bit (at 5600K) and then calibrating. However, I discovered that the ugly lines become visible again as I slide the color temp down, and at 2500K the image is once again unusable. Turning the Rec709 LUT on makes it even worse, contrary to my hope that the crushed blacks would hide the noise. This gels with what happened when I tried to grade the shots I mentioned above. Adding the usual amount of contrast (but not lifting) made the FPN more visible. And those shots were indeed shot at a lower color temp in order to skew things toward blue. Leaving the camera run at this lower color temp for 10 minutes and then calibrating again did nothing.

    SO BOTTOM LINE -- FPN/colored vertical lines at 800 ISO, no lifting, visible even in the higher end of the shadows albeit may only be seen with motion, crushing shadows a bit (LR set to about .150) makes it worse and makes the noise more "colorful", as does viewing in Rec709, calibration with body cap after running cam for 10 minutes does initially clean up the blacks, but the noise returns to an unacceptable level as you lower the color temp. So the calibration basically only works if you stay at 5500K or above (higher temp lessens noise). This all seems wrong to me. My understanding is that you should not be seeing any FPN at ISO 800 without pushing it in post. Thoughts?
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  2. #2  
    Senior Member
    Join Date
    Jan 2013
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    Southern California
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    Contact support and ask them. They will probably ask for some DNGs
    Quote Originally Posted by Nick_Michael View Post
    Hi. Had my UMP since April/May and recently began noticing what may not be the traditional FPN (monochrome vertical lines evenly spaced across the whole image) but more of the blue-ish vertical lines randomly spaced across the whole image. Like someone dipped a comb with random missing teeth in blue paint and ran it down my entire frame from top to bottom -- if we want to get creative about it. Can't post any stills right at the moment but I will, and of course I am planning to contact BMD about it but I thought I'd float this out there as I prepare some samples and see if anyone else has dealt with this. What alarms me is that I am seeing this in images shot at 800 ISO without any lifting in post, and shots that were taken following a calibration where I left the camera on for 10 minutes prior. The range of the image it appears in is also alarming - not just the darkest shadows, but dark-colored objects that are otherwise well-lit. Like a dark shirt a subject is wearing that is being directly hit by the key light. In these cases you may not see it in a still (I will be uploading short clips as well for this reason) but motion really gives it away. It's like you're looking at his shirt through prison bars.

    I've run some tests with the body cap where I run signal to my 40" LCD via SDI-HDMI converter and do indeed get cleaner results after running it for a bit (at 5600K) and then calibrating. However, I discovered that the ugly lines become visible again as I slide the color temp down, and at 2500K the image is once again unusable. Turning the Rec709 LUT on makes it even worse, contrary to my hope that the crushed blacks would hide the noise. This gels with what happened when I tried to grade the shots I mentioned above. Adding the usual amount of contrast (but not lifting) made the FPN more visible. And those shots were indeed shot at a lower color temp in order to skew things toward blue. Leaving the camera run at this lower color temp for 10 minutes and then calibrating again did nothing.

    SO BOTTOM LINE -- FPN/colored vertical lines at 800 ISO, no lifting, visible even in the higher end of the shadows albeit may only be seen with motion, crushing shadows a bit (LR set to about .150) makes it worse and makes the noise more "colorful", as does viewing in Rec709, calibration with body cap after running cam for 10 minutes does initially clean up the blacks, but the noise returns to an unacceptable level as you lower the color temp. So the calibration basically only works if you stay at 5500K or above (higher temp lessens noise). This all seems wrong to me. My understanding is that you should not be seeing any FPN at ISO 800 without pushing it in post. Thoughts?
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