Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!uunet!wuarchive!zaphod.mps.ohio-state.edu!sdd.hp.com!ucsd!pacbell.com!pacbell!pbhya!whh
From: whh@PacBell.COM (Wilson Heydt)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: Screen Photography
Message-ID: <41685@pbhya.PacBell.COM>
Date: 23 Aug 90 17:24:45 GMT
References: <9034@ur-cc.UUCP>
Reply-To: whh@PacBell.COM (Wilson Heydt)
Distribution: usa
Organization: Pacific * Bell, San Ramon, CA
Lines: 37

In article <9034@ur-cc.UUCP> bfag@uhura.cc.rochester.edu (Meneldur) writes:
>Greetings.
>
>A question for those of you who have taken pictures of your VGA screens.
>What exposure time is most appropriate?  I know it needs to be long enough
>to avoid the screen retrace, but what is optimal?

The "classical" answer is to use the reciprocal of the full screen repaint
time.  Find out how long it takes to fully draw the screen and use that.
(The reason I said "classical" is that for a TV set in the US, the time is
1/30 second.)

>I recently took slides of some color diagrams done with the paint program
>included in Windows 3.  I figured 1/8 second should be adequate, yet the 
>slides demonstrated broad diagonal swaths of darker colors that appear to
>be retrace related.  Otherwise, the results were quite nice using the
>Zenith FTM monitor.

You may be having problems with a focal-plane shutter.  The older leaf
shutter didn't tend to do that.

>Thanks for the help.  I'd rather not have to use another roll of film
>experimenting with various exposure times!

Why not?  Film and processing are cheap.  Get a short roll (say, 12
exposure, you'll be spending no more than $5 or $6 for everything)
and try different timings and apertures.  Then makes notes somewhere
you won't lose 'em--say a file on your system--and you won't have to
do it again.

	--Hal

=======================================================================
Hal Heydt                    |    An earthquake is Mother Nature's
Analyst, Pacific*Bell        |    "silent" pager going off . . .
415-823-5447                 |   
whh@pbhya.PacBell.COM        |