Re: Flicker?

Craig Miller (cvmiller@uhunix.uhcc.Hawaii.Edu)
Tue, 17 Jan 1995 13:03:58 -0500


At 11:43 PM 1/16/95, Michael Sattler, San Francisco wrote:
>At 10:49 1/16/95, Patrick Delahanty wrote:
>
>>Is there any way to reduce flicker when you point a camera at a Mac, PC, or
>>TV?
>
>Some full-time video geek would know better, but I believe what you're
>seeing isn't flicker (from intensity variations in the displayed images)
>but a difference in synchronization: the "top left" of the image being
>displayed isn't in synce with the "top left" of the camera that's watching.
>That "flicker" you're seeing is the dead time between screen draws.
>
>I'm guessing that when professional videographers (camera monkeys) shoot
>pictures of cameras, they have some hardware way of syncing up the systems.
>
Yes in fact us camera monkeys (I prefer to be called a broadcast engineer)
actually have special sync generators which work at 24 fps (normal TV is
just under 30 fps) so that when a TV is shot on movie file it looks
'normal'. This is the only place in the world (that I know of) where you
will see 24 fps video (NTSC (US & Japan) is 30, and Europe, and most of the
rest of the world is 25 fps).

Hope this clearifies the situation. Or atleast brings you in sync. ;-)

Craig...

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Craig Miller 808/539-3661
Digital Media Lab Coordinator 808/539-3833 fax
University of Hawaii cvmiller@uhunix.uhcc.hawaii.edu

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