[Open-graphics] Re: CPU-based graphics card

[Hamie]

On Sunday 22 April 2007 00:33, Timothy Normand Miller wrote:
> On 4/21/07, Dieter <netbsd at sopwith.solgatos.com> wrote:
> > I wonder why films can get away with 48 Hz, but CRTs are annoying at 70
> > Hz?
>
> I think it has something to do with motion blur.  A CCD takes very
> little exposure for a frame, while film, I think, has a longer
> exposure period.  So you get more motion blur with film than with a
> CCD.  Also, there may be something to the way the TV scans the image,
> while the film projector flashes it all at once.  Note that I could be
> totally full of crap here, so you may want to look elsewhere.  There
> are people who know the answer to this question.

Not blur AFAIK. But more the fact that the film is a whole frame at once 
(Sorry, we did look at this at Uni about 20 years ago, it's beena  while :).
Similar to an LCD in fact... 

A CRT on the other hand is scanning from top to bottom... So by the time the 
beam gets to the bottom of the screen, the top has started to fade already. 
You can fix this by using a longer persistence phosphor, but that introduces 
ghosting/motion blur. 

Hamish.,
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