Thread: Whats this black spot on my new Black Magic pro images?

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  1. #1 Whats this black spot on my new Black Magic pro images? 
    Any thoughts as to what this dark spot on all the footage from my new URSA Mini Pro might be? its right at the bottom about 2/3 of the way across, on the right side. It appears in all images. I have tried 2 different lenses and all ND filters and its always present, slightly blurred, focus never changes which leads me to believe its on the sensor. Camera arrived 6 days ago new from BH Photo. Youtube has degraded footage to the point its hard to see. Ill shoot against white screen in am


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  2. #2  
    Senior Member misterkofa's Avatar
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    Sorry, didn't see anything. A still frame would probably be better with an arrow or something pointing to the area.
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  3. #3  
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    The only spot I can see comes into focus towards the end of the clip when the dog's back leg also comes into focus as the lens focus adjustment moves. If there is a blemish in the image caused by a spot on the IR filter panel it should become more distinct when the lens aperture is closed to f16 or thereabouts. If there is a mote of dust on the sensor itself, it likewise should appear more distinct when the lens iris is closed towards f16. Spots on the sensor are generally more distinct.

    If the spot is on the front of the IR panel it should be removable with the careful touch of a lens air brush ( blower brush ) or a brief shot of canned air through its tiny plastic straw. Canned air should be used very carefully and the straw kept well away from touching the glass surface. It has a chilling effect on optical glass and may crack a thin piece like an IR filter, so, a brief shot only and not a sustained blast.

    The can should always be used upright and never shaken before use. If liquefied gas becomes entrained in the gas flow, a slug of liquid gas will near-freeze anything it touches. Shock cooling of critical parts is never a good thing. Wear glasses too. An edge flake of optical glass from the rear element of a lens or rim of filter glass in the eye is not good. A slug of liquified gas freezing a spot on your eye may spoil your day.

    If the spot is on the sensor of a UMPro, then it is for the serviceman to repair because there is the ND filter system in front of the sensor to deal with. This is not a task for the average inspired amateur who has no air-filtered clean room to work in.
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  4. #4  
    I can't see this either. The only thing I noticed was a spot on the floor itself that moved in and out of focus. You probably need to superimpose some kind of arrow or circle around what you're asking us to see so we know where to look.
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  5. #5  
    Ill work on getting a better screen shot tomorrow, its lost in the upload to youtube but is in every clip Ive filmed same spot, never changes with focus adjustments, lens changes.

    looking back at all footage it appears to only be on the shots with filter in position 1 so maybe its a spec of dust I missed. Ill get one of the guys with better eyes to look in the morning. Thanks for input
    Last edited by panaceabeachbum; 11-29-2017 at 09:42 PM.
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  6. #6  
    This will sound like I’m being a jerk but I’m honestly not... have you made sure it’s not your monitor? Have you seen this on more than one screen? I only bring it up because I have had that happen to me; I thought there was something on the lens / sensor in an interview but quickly discovered it was an old monitor.
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  7. #7  
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    Quote Originally Posted by digitalinnovations View Post
    This will sound like I’m being a jerk but I’m honestly not... have you made sure it’s not your monitor? Have you seen this on more than one screen? I only bring it up because I have had that happen to me; I thought there was something on the lens / sensor in an interview but quickly discovered it was an old monitor.

    Not a jerk, I looked at the video and said damn there’s crap everywhere, oh wait, that’s my monitor.
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  8. #8  
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    Me too, the first VAs had a dark spot on them, and it thought it was the camers at first.
    Cheers
    Last edited by Denny Smith; 11-30-2017 at 08:32 PM.
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  9. #9  
    Shine a flashlight at an angle to see dust on filters/lenses easier. Honestly if you aren't stopped way down it's probably something else. I had some sensor dust on my bmpc 4k and didnt notice it until I was at f14
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  10. #10  
    Flashlight at angle did it. It appears someone let a drop of sweat or similar drop on the clear window closest to the lens, either during assembly or when the windowed cover was added at BH , unsure. Would have had to have happened when camera was pointing straight up with cap off, which I havent done. Cleaned right off with canned air and a tiny optical brush. was about 1/16" diam spot. Tried to only touch right at the spot .
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