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  1. #1

    Ghosting effect with fast movement

    Happy Easter from England.

    So, I'm sitting at my desk trying to catch up with some work and I'm trying to decide how to pluralise the word 'forum'. Do I go with my instinct and just stick an 's' on the end, or do I appease the pedants and use 'fora', running the risk of many people not knowing what that means.

    Turning to Google for guidance (I know, I know) I discover the best suggestion by far comes all the way from New Zealand and a new-to-me website called mediacollege.com.

    And it's got photography and video sections. And the top thread in the video posts contains the best explanation of shutter speeds and frame rates that I've ever read.

    I think I'm going to like it here.

    Beemerchef from Texas asks a great question: is there a guide to combining shutter speed, frame rate, light conditions and movement? I would love something like that! In fact, I'd throw in bit rate, too, Beemerchef (do you cook German cars?). I think data rate my have something to do with getting smooth movement, as well.

    Here's my problem: http://youtu.be/voKInpe8abA

    How do I stop the athletes looking like they have three pairs of legs due to the 'ghosting' effect that comes with the fast movement, especially after around 2min 30sec?

  2. #2
    Administrator Dave's Avatar
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    Hi Martyn, welcome to our "forums" and thanks for the kind comments. We aim to please

    The problem with your video looks like an interlacing issue to me, rather than shutter speed. Are you familiar with how interlacing works? If so, follow your production and post-production workflow to make sure your interlacing settings are consistent all the way through. I'm guessing that somewhere along the line your field dominance has become reversed. In other words, changed from "even first" to "odd first" or vice versa.

    If you'd like more information about interlacing, let me know and I'll see if I can put something together. To be honest this is something we should cover here anyway so I'll put it on the to-do list.

    BTW, after you've seen this message I'll probably move this discussion to a new thread since it's a new topic.
    Dave Owen
    MediaCollege.com

  3. #3
    Thanks Dave.

    I wondered if my problem was shutter speed/frame rate-related but if we're going to look at interlacing, yes, you should move the discussion. Apologies for drifting.

    My knowledge of interlacing is very basic so I would really appreciate a guide to the principles.

    In the meantime, I will look at my processes and see if I swapped the fields somewhere along the way during input/output and any conversions I might have done.

  4. #4
    Administrator Dave's Avatar
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    Cool, I'll get onto this ASAP. Interlacing has become a bit more of an issue since some HD formats came out with a different field dominance to the old DV standard, so I suspect a few people are coming across this. I'll reply again when I've got something together.
    Dave Owen
    MediaCollege.com

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