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weird rolling moire problem with NEX-5n + high shutter speeds (video)

Discussion in 'Sony Alpha E-Mount Cameras' started by rungunshoot, Feb 12, 2013.

  1. rungunshoot

    rungunshoot TalkEmount Rookie

    16
    Feb 12, 2013
    I've been filming with the NEX-5n for a while and never quite got this issue solved. And now seeing as how the 5r and NEX 6 have downgraded the video quality a notch, it looks like I won't be upgrading any time soon.

    When I'm filming at a high shutter speed (above 1/160 or so), a bizarre rolling rainbow moire randomly appears in the image occasionally. You can see it at 2:22 in the video here:

    https://vimeo.com/36213951

    Anyone have any experience with this, or any tips on how to avoid it (other than reducing shutter speed)? Wondering if my camera has a defect. Thanks!
     
  2. rungunshoot

    rungunshoot TalkEmount Rookie

    16
    Feb 12, 2013
    Here's a sample of the issue I just uploaded to Vimeo:

    [video=vimeo;59504237]https://vimeo.com/59504237[/video]
     
  3. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    I always shoot at the correct shutter speed, so I never saw this on my NEX, but it looks like a slight problem with the sensor readout.

    Do you shoot 24p or 60p (or 25 or 50, depending on which region you are)? If you shoot 25p, for example, use 1/50 of a second as shutter speed. If you shoot slow motion 50p, use 1/100 of a second. Don't use ANY other shutter speed! Control your lighting with the aperture, ISO and (vario) ND filters, then this problem should not appear.
     
  4. rungunshoot

    rungunshoot TalkEmount Rookie

    16
    Feb 12, 2013
    Cool, I was trying to avoid using Variable ND's because I use ReelSmart Motion Blur in post to control shutter angle when editing. I haven't had this problem with any other cameras I've ever used, so I was hoping I had a defective NEX-5n. I suppose filters may be the only option.
     
  5. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    Oh, haven't thought about this ... But I also don't think it's a defect model because it rather seems like a readout (and therefor software) issue.
     
  6. rungunshoot

    rungunshoot TalkEmount Rookie

    16
    Feb 12, 2013
    I shoot 24p primarily and follow the 180 degree rule more-or-less when shooting indoors. Outdoors, I've been using the plugin ReelSmart Motion Blur to re-create the motion blur in post. It sounds hack-y, but it provides surprisingly good results and allows me to forgo ND's entirely.

    So I was hoping I just had a defective camera and a repair/replacement would allow me to continue my software solution. But more than likely I'll just have to suck it up and use my ND's.
     
  7. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    You can still try to get a replacement and see if it behaves the same. I'm just guessing here as I don't have a NEX-5N.

    As for the NDs - why don't you like to use them? I never saw a problem using ND filters in video - even variable ones don't decrease resolution enough to be visible in 2K video.
     
  8. rungunshoot

    rungunshoot TalkEmount Rookie

    16
    Feb 12, 2013
    There are a couple of reasons I don't like using them. First, there's the awkward 2 stops of mandatory light loss. I find myself awkwardly attaching and removing the filter when going from shade to sunlight, indoors to outdoors, etc. If I'm following an unpredictable subject in a documentary fashion, this can cause problems.

    Second, I hate having to adapt every lens to my Variable ND filter with stepper rings because of the hassle of managing the rings. The other option is of course to carry more ND filters, which means more filter bags and more things to screw/unscrew every time I want to change lenses or lighting conditions.

    These are only issues because I shoot solo in a very run-and-gun style (hence the name), and any extra hassle I can take off my plate is a benefit. If I was primarily shooting locked-down narrative stuff, I wouldn't complain about the extra effort. But then again I probably wouldn't be shooting on a NEX-5n either.
     
  9. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    Ah, okay. I shoot mostly scripted scenes for Ads and similar things, so I, of course, don't have a problem with ND filters. Too bad Sony doesn't keep an eye on NEX-x video performance. They probably want to sell more NEX-VG / NEX-FS cameras.
     
  10. rungunshoot

    rungunshoot TalkEmount Rookie

    16
    Feb 12, 2013
    Just thought I'd close out this thread. My NEX-5n was defective. I tried another camera body and did not have the same problem.