Archived posting to the Leica Users Group, 2002/02/17

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Subject: Re: [Leica] OT: 16mm projector shutter speed
From: Bernard Cousineau <flatbroke@sympatico.ca>
Date: Sun, 17 Feb 2002 17:58:14 -0500
References: <F992E587-23EE-11D6-B5DD-0003930C1F28@bigfatpipe.net>

> i have an old 16mm projector that i got at a thrift store.  i plan to
> try using it to light some nudes--i'm going to try projecting a movie
> onto my model.  i'm windering how to be sure i get the right amount of
> exposure, since my light source will be flickering.  i'm *thinking* the
> shutter speed on a movie projector is 30 fps.  if that's correct, then
> i'm thinking shooting at 1/30 will guarantee me getting only one
> illumination per frame.  is that right?
Brad,

Your projector should run pretty close to 24 fps, but many projectors will show each frame twice to minimize the apparent flicker. This means that each frame will be on screen for either slightly less than 1/48th or 1/24th. On top of this, some
projectors have been modified to run at 30 fps, showing each frame only once. The purpose of this is to facilitate cheap video transfers. If you are in a country where video runs at 25fps, your projector may have been modified to run at that speed.
What I suggest is to run a test first at speeds between 1/8th and 1/60th and see what works best.
The easy way out, of course, is to dupe the frames that you want and use a slide projector.

Bernard
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Replies: Reply from "Mike Durling" <durling@widomaker.com> (Re: [Leica] OT: 16mm projector shutter speed)
In reply to: Message from bourgeois and biblical <bwdaly@bigfatpipe.net> ([Leica] OT: 16mm projector shutter speed)