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Path: utzoo!watmath!watnot!watcgl!onfcanim!dave
From: dave@onfcanim.UUCP (Dave Martindale)
Newsgroups: net.graphics
Subject: Re: Re: Film Recorders
Message-ID: <14757@onfcanim.UUCP>
Date: Sat, 23-Nov-85 04:10:15 EST
Article-I.D.: onfcanim.14757
Posted: Sat Nov 23 04:10:15 1985
Date-Received: Sun, 24-Nov-85 07:45:36 EST
References: <14752@onfcanim.UUCP> <651@dicomed.UUCP> <14755@onfcanim.UUCP> <860@osu-eddie.UUCP>
Reply-To: dave@onfcanim.UUCP (Dave Martindale)
Organization: ONF, Montreal
Lines: 39

In article <860@osu-eddie.UUCP> julian@osu-eddie.UUCP (Julian Gomez) writes:
>
>Film format changes are nontrivial. It is considered a semi-major
>operation, and if anybody wants something exposed in a format other
>than what's currently mounted, it has to be requested a few days in
>advance.  There's a lot of jiggling and tinkering that has to be done,
>including a test exposure to make sure the mounting was done correctly.

There are actually several ways to do a format change.  If you want
the maximum resolution, you want to be using as much of the tube area
as possible for the image, and so you have to change camera and lens
positions, refocus, reset image sizes and positions.  Yes, it's a lot
of work.  And, of course, since each format is a different magnification,
you have to redo your exposure tests and thus have different film
calibration data for each format.

On the other hand, if you just want fast format changes, you set up
the mechanical part of the system to handle the largest format you do
(say 36mm slide) and then shoot the smaller formats using the same
setup, using smaller areas of the tube face.  You can use all the
same exposure data for all the formats.  A format change is just
entering a different bunch of numbers to reposition the image
and changing the camera aperture plate.  (If you have a fixed-format
camera stand, this is the only way you can go about changing formats).
The Celco makes this easy by having the camera aperture plate in use
cause the recorder to select between two different sets of size and
position adjustments, and rotate the image on the tube, so you can have
the system permanently set up for 35mm slide and cine, or 35mm slide and
16mm cine for example.

So you have a choice.  If you're fussy, you do it the hard way; if you
want to switch formats easily you can avoid the hard work.  Of course,
if you're making a drastic switch in format (35mm to 70mm or 4x5),
you probably have to switch lenses too and you can't avoid all the
readjustments.

The above comments apply specifically to a Celco; I don't know what
Dicomed does, but if a variable-format stand is available, it probably
works in a similar manner.