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Do frame rate and shutter speed sync?
  • Hey, I'm the proud owner of GH2 since a couple of weeks and have steadily been learning about DSLR photo and video. Now there's one thing that is not entirely clear to me. It's about the sync between video frame rate and shutter speed. Are these synced, ie. the shutter triggers a cycle when a new frame capture starts? Or do they run independently from each other? If it's case 1, what happens when shutter speed is slower than the frame rate, ie. it takes longer than 1 frame for the shutter to open and close?

    Thanks for any clarifications, Dieter

  • 6 Replies sorted by
  • Actually, there isn't really a shutter in the mechanical sense being used; rather the sensor is being read at different intervals. The shutter speed remains at whatever you set it (except in some automatic modes where shutter is varied to adapt to lighting - like in A or P modes). If the shutter is set to a value that exceeds the frame rate the camera duplicates frames instead of capturing new ones.

  • Thanks!

  • I have a GH1 and in manual mode it prevents me from selecting a shutter speed slower than the frame rate (i.e. the slowest shutter speed I can get at 24 fps is 1/30).

  • yes i am. i asked the question to get a grip on cases where you need or want to deviate from the standard rules. btw, i take those 'rules' as hints but it's what works that works for me ;)

  • AFAIK the 180º shutter rule was a mechanical design limitation of film cameras that can be broken at will when digital is used. If the light is low I wont hesitate to use a 360º shutter and get twice the light in.

    However, Pros will probably tell you that a 1/48 shutter speed (SS) gives 24p film an unique "look". I'm not experienced in the "look" subject, so I can't say much more than this.

    Shutter speed and frame rate many times are not in synch especially when SSs are slower than 1/25s : http://www.personal-view.com/talks/discussion/2396/gh2-motion-fluidity-360º-shutter-test-on-slow-shutter-speeds

    On faster SS I don't know, but with a strong light it's more or less easy to test. You just need to put the camera on tripod, point it at that light and pan it fast enough. Check for interruption on the light trials.