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From: dave@onfcanim.UUCP (Dave Martindale)
Newsgroups: net.rec.photo,net.columbia
Subject: Re: What kind of film do the astronauts use?
Message-ID: <14789@onfcanim.UUCP>
Date: Mon, 3-Mar-86 23:44:46 EST
Article-I.D.: onfcanim.14789
Posted: Mon Mar  3 23:44:46 1986
Date-Received: Wed, 5-Mar-86 03:32:37 EST
References: <1086@decwrl.DEC.COM> <1972@peora.UUCP> <510@tekig4.UUCP> <2207@utcsri.UUCP>
Reply-To: dave@onfcanim.UUCP (Dave Martindale)
Organization: ONF, Montreal
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Xref: watmath net.rec.photo:1877 net.columbia:2557

In article <2207@utcsri.UUCP> hofbauer@utcsri.UUCP (John Hofbauer) writes:
>> fit a Hasselblad.  Also, the Hasselblad couldn't be being used for moving
>> pictures, could it?
>
>Sure it could. Film is film is film. The 35mm film you use in your
>favourite SLR is fundamentally the same as used in making feature
>films. There are even mail order companies which repackage movie
>film for use in still cameras. They advertise it my its code number:
>5257, or some such number.

Second things first: It's 5247, and very commonly used in motion picture
work, and *not recommended* (by Kodak) for amateur use.  In the first
place, it is designed to be properly colour-balanced when exposed for 1/50
second, with little attempt to make it work properly at long exposure times,
since you generally don't get long exposures in movie filming, even in
animation.  Also, its density-vs-exposure function is very linear but
shorter than that of amateur films, giving less exposure latitude.

And no, a Hasselblad couldn't be used for moving pictures.  It certainly
couldn't be run at 24 frames per second, normal filming speed, and what
would have been used in most IMAX filming in space.  It couldn't even
be used for single-frame animation work, since it has no method for
accurately registering the film from frame to frame.  Real movie cameras
all strive to register the film accurately, to minimize jitter on the
screen.  Many use registration pins that fit into the sprocket holes
of the film.

IMAX cameras pay particular attention to registration, since part of the
impact of IMAX depends on very good stability on the screen.  The camera
has *four* registration pins.  A spring-loaded metal bar presses on one
side of the film, forcing its other side against a fixed metal bar.
Finally, the pressure plate behind the film has a vacuum applied to it to
hold the film flat during exposure.  The projector also uses registration
pins, but I haven't had a good look at one so I can't comment further.
The acceptable frame-to-frame registration tolerance for the IMAX format
is apparently .0004 inches.

There are similarities though.  IMAX cameras use Hasselblad lenses.
The IMAX frame is about 2.2 x 2.77 inches, similar to a Hasselblad
(and three times the size of normal theatrical 70mm).