Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!ucsd!ucbvax!van-bc!mdavcr!ewm
From: ewm@mdavcr.UUCP (Eric W. Mitchell)
Newsgroups: comp.sys.mac.misc
Subject: Re: digitizing with a video camera
Message-ID: <976@mdavcr.UUCP>
Date: 28 Aug 90 17:48:51 GMT
References: <5368@ptsfa.PacBell.COM>
Distribution: na
Organization: MacDonald Dettwiler, 13800 Commerce Parkway, Richmond, BC, Canada  V6V 2J3
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In article <5368@ptsfa.PacBell.COM> rkm@PacBell.COM (Richard Mossman) writes:
>From my readings on rec.video, I would tend to believe that the reason you
>get low resolution scans from a paused VCR is because you and your scanner
>are only seeing a single field and not a full frame (2 fields = 1 frame).  I
>tried taking some photos from a television screen of a paused VCR picture of
>a face and got something that was recognizable but streaked and very grainy.
>Basically you are only getting half the picture information.

If you want to take pictures of your TV screen, you should set your
shutter speed to 1/30 second, then adjust aperature for suitable light
level.  Since your TV scans at 60Hz, and you need two scans to get a
full picture, you will get the best results.  If you use something other
than a multiple of 1/60 second, you will get bands of brighter regions
on the screen where the raster has scanned twice (or more) during the
exposure.

I've had my best results using the above scheme.  They actually weren't
too bad.


>I would also like to know what you mean by "digital VCR".  I didn't know these
>existed.  What manufacturer?  Model?  Is it performing a digital recording of
>both video and audio?
>-- 

There is still no such thing as true digital VCR.  The term now
represents more marketing hype than anything.  Manufacturers know that
the buzz word is associated with higher quality (due to CDs), so they
are mis-using it freely.  Images are still stored in the same analog
format on tape.  The difference (as I understand it) is simply that the
tuning elements, etc, are digital.  Note that this may indeed result in
a better picture, but it isn't "digital".

Of course, I'm speaking only about consumer electronics.  I am unaware
of what may be available for commercial use.

Eric

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