It is important to be able to measure curtain speed on both the opening and
closing side, as close to the edge as possible, to judge how erratic curtain
speeds are. I don't know the specs for those shutter testers (they may be
old Kyositsu model numbers), but 11.7 to 12.1ms are the guidelines I've
always used for OM-1 setup.
John Hermanson
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Camtech, Olympus Service since 1977.
21 South Ln. Huntington NY 11743-4714
631-424-2121 http://www.zuiko.com
Free Olympus Manuals: 1-800-221-3000
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----- Original Message -----
From: Mark Marr-Lyon <o9938156@xxxxxxxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Wednesday, March 22, 2000 1:27 PM
Subject: Re: [OM] mechanical and electrical shutter
> C.H.Ling wrote:
>
> >Yes, 11ms is a time, the time for the shutter curtain to travel from
> >one edge to the other. I remember it was 11-12ms for the OM-1, but
> >there could be other interpretation, such as the complete cycle or the
> >time to cover only the 36mm frame.
>
> In the om-1 manual, it says "Use the shutter tester 7F7L1 and/or 7F7L3.
> The speed should be 11.7-12.1ms at 1/1000 sec.", but it also has the
> diagram showing 13.5ms from one edge to the other. I have no idea
> what the 7F7L1 or 7F7L3 shutter testers are, but I was wondering if
> there is some standard distance that these testers measure the travel
> times over. It makes sense that the time specified from the tester is
> smaller than the time it takes to travel the whole frame, since it would
> be easier to make a tester that measured the time over some distance
> smaller than the frame.
>
> >I expected the shutter tester will only measure one point, one point
> >at a time or a few point across the frame, it will not take average of
> >the whole frame. It is very important to check the equivalent shutter
> >speed at different area across the shutter, at least you have to check
> >the left edge, center and right edge for a horizontal travel shutter.
>
> The exposure time can be measured by only using one sensor, which I've
> already done. There is a definite deviation in exposure time between
> the left and right sides of the shutter, which is why I want to measure
> the curtain speeds. I can infer that the closing curtain is moving
> faster than the opening curtain, since the exposure time is smaller
> on the left (from the back) side of the shutter, but I can't tell what
> the actual errors are in each curtain. Two sensors (at least) are
> necessary to do this, and I was trying to figure out how far apart to
> mount them to get the times specified in the repair manual.
>
> I realize that I'm probably splitting hairs about this, but I'm also
> having fun doing it :)
>
> Mark Marr-Lyon
>
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