[plug] neo's wm

[Steve Baker]

----- Original Message -----
From: "Christian" <christian at amnet.net.au>
Sent: Saturday, February 23, 2002 10:01 AM
Subject: Re: [plug] neo's wm


> On Sat, Feb 23, 2002 at 08:43:46PM +0800, Andrew Pamment wrote:
>
> > and have you ever filmed a computer monitor? not an LCD one, but an
> > ordinary crt monitor. i bet the aliens had a hard time working that one
> > out, last time i saw a tv show with a real monitor on it, and i don't
> > watch tv anymore so it was some time ago, it flickered horibly. i think
> > they proberly filmed it, then added the contents of the screen later.
>
> TV isn't usually filmed, it's videoed.  I'm not sure whether the flicker
> on CRTs is primarily to do with the interlacing effect of video or
> simply the refresh rate and frame rate not matching (which is what I've
> always assumed).  But, now that you point it out, I don't remember ever
> seeing a CRT flickering on filmed material, only videoed, so it could be
> an interlacing artefact after all.  (This is only based on my memory
> though so may not actually be the case.)
>

Pretty close.  Actually, it's not because the refresh rate and frame rate
don't match, it's because the *shutter speed* on the camera and the refresh
rate of the monitor don't match.  The shutter speed and the frame rate don't
necessarily have to be the same, although with most consumer cameras they
are.  Professional TV cameras, and I'm guessing film cameras too, have an
adjustable shutter speed.  A guy at work on Friday had a professional
digital video camera, and he was filming our monitors and there was no
flickering at all once he adjusted the shutter speed correctly.  Then he
pointed the camera at another monitor with a different refresh rate and it
was flickering like crazy.

Regards,
Steve
--
Steve Baker
Open your mind, then check out www.nexusmagazine.com