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Thread: Canon XF100 color and noise issues - Used Primarily for Green Screen Work

  1. #1
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    Question Canon XF100 color and noise issues - Used Primarily for Green Screen Work

    I am using the XF100 primarily for greenscreen use. I got it specifically because of the 4:2:2 color space. I will first say that the chromakeying seems to be more than twice as good in terms smoothness on the edges.

    My main issues right now with the camera (and these have been pointed out by a review I read somewhere) are:

    With no color profile selected there is some significant sharpening going on. My subject has a white line around them and that is only because of some kind of sharpening algorithm.
    The skin tone is terrible. Very orange.
    NOISE. I have 2000 watts of fluorescent light directly on the person and at least 3000 on the greenscreen.

    All of these issues are workable. I can color correct the skin tone and we figured out how to reduce the noise by going -6.0db and 2.8 fstop.

    I am using 3 canon hm400 cameras for other angles and I was under the impression that all these cameras use the same chip. The hm400s don't key as good but the color reproduction is way better and also there is almost no noise compared to the xf100.

    Is anyone using this camera for serious green screen work and if so do you like it and do you have workarounds/recommendations for these issues?

    FYI this is my first pro camera and I really wanted to send it back after viewing the first bit of test footage. I don't understand why it has to be at -6 db of gain to get decent footage. I have had thoughts that maybe with all the trouble in Japan some cameras come out better than others and I have a bad sensor??

    Thanks

    Aaron

  2. #2
    Tropical Legend cgbier's Avatar
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    Are you doing a custom white balance to prevent your orange skin color? Are those household fluorescent? Most of them suck. If you have to shoot with -6dB @ 2.8, you should over think your lighting strategies. for a one person shot you have too much light. That might be your issue. You are over taxing the sensor. I have an Arri 3-head kit with a total of 1100W. That's all I ever needed for a keyed head/chest shot. Tell us a bit more about your set up.

    Noise? I only saw some noise when I had to crank the gain up to 12dB.

    I haven't done any chromakeying yet with it, buy I am nothing but flattened by the quality I get out of this little baby.

    Can you give us a still from your scene (use the photo function) with all necessary data - shutter speed, iris, gain.

    FYI this is my first pro camera
    Don't get me wrong, but this might be another issue you have. The XF is NOT a point and shoot (even though it works nicely when set to fully automatic). You have to put some thoughts into your settings.
    What you call a grumpy German? - Sour Kraut

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    Tropical Legend cgbier's Avatar
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    That one was shot with an HV30. 300W and a bounce card for the two talents, 150W for the background.

    150w.jpg
    What you call a grumpy German? - Sour Kraut

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    Default Reference images

    Here are some images. We went brighter with the lights than normal to try and correct the noise...it helped but things are a little more exposed than I would normally want.

    I can't get the meta data because I can't open my mxf files in xfutility as I dumped them all via usb3.0 card reader...

    I am fairly certain that the relevant settings were -6.0db gain, 2.8 fstop, no color profile.

    In response to your comment about over taxing the sensor. That sounds great but can't really be the case...surely shooting in daylight outside would be way more taxing than 2000 watts.

    Aaron


    Quote Originally Posted by cgbier View Post
    That one was shot with an HV30. 300W and a bounce card for the two talents, 150W for the background.

    150w.jpg
    Attached Images Attached Images

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    Tropical Legend cgbier's Avatar
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    You sure those are sharpening artifacts? To me it looks rather like the camera is trying to compensate for aliasing due to too much contrast.
    Noise: With that luminance level you won't see noise. The camera can't make up its mind what color to show, so it simply mixes them up.
    Orange: Custom white balance! While the auto WB is great in standard light, it sucks with those pigtails - especially "daylight" balanced. With mine on auto, I have nasty color pumping with skin colors all over the place from green to orange.
    What you call a grumpy German? - Sour Kraut

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