RE: [APML] focus hocus pocus

["Richard Klappal" <klappal@xnet.com>]

Scott:
	It's my recollection that all of Canon's FD mounts had the same body
thickness (bayonet to filmplane).

Holding a straightedge across the front face of the bayonet, and measuring
to the film plane marker on the top of the body (circle with a line marking
the film plane, just left of the penta-prism) I get 42mm (as exact as I can
read) on both my F1 and A1.  My F1 is the original version, before the
A1/AE1/AE1P era.  You should be able to use one body for focus, and the
other for imaging.

If they still make it, Celestron used to have a "Multi-Function Focal
Tester".  You would unscrew the FD format T-adapter, and screw the "MFFT" in
its place.  It has knife edges and Ronchi Grids for focusing, and was
designed for exactly this purpose.  After focusing, put the T-adapter back
on, and mount the camera.

If they don't still have it, you might find one through ebay or something.

Richard


-----Original Message-----
From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On
Behalf Of Scott Hammonds
Sent: Friday, March 22, 2002 07:56
To: astro-photo@seds.org
Subject: RE: [APML] focus hocus pocus


Matt,
I noticed the same problem about the film laying completely flat.

I do have a spare body, but it's an AE-1 vs AE-1P which may have a different
distance to the film plane. I didn't think about the difference, I need to
get a measurement using the method described by the link you sent before to
find out if there is a difference.  I also noticed that the different film
thicknesses could create a problem.  How do you compensate for that with
your KE?

Scott Hammonds

 ... trimmed ...



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