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From: raveling@vaxb.isi.edu (Paul Raveling)
Newsgroups: comp.graphics
Subject: Re: photographing computer screens
Message-ID: <6831@venera.isi.edu>
Date: 18 Nov 88 17:30:41 GMT
References: <8811042303.AA21505@dawn.steinmetz.GE.COM> <76649@sun.uucp> <2663@pixar.UUCP> <7896@bloom-beacon.MIT.EDU>
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Reply-To: raveling@vaxb.isi.edu (Paul Raveling)
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In article <7896@bloom-beacon.MIT.EDU> tada@athena.mit.edu (Michael Zehr) writes:
>Some of the photo places have pointed out that the automatic color balancing
>by the machine developers may throw the color off as well.

	Some screen image pictures I did earlier this week suggest
	this is the prime culprit.  It also turned out that a few images
	got suboptimal exposures when there was either a dark or light
	area at the center of the frame; that's due to the camera
	using center-weighted averaging for automatic exposure.
	It's possible to anticipate this by guestimating how much
	each zone of the image will influence metering, but bracketing
	is still the safest approach.

	Another source of amusement is Moire patterns in the finder.
	At some distances the granularity of the raster and the focusing
	screen's Fresnel lens match closely enough to generate
	colored patterns.


---------------------
Paul Raveling
Raveling@vaxb.isi.edu