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Subject: Re: Optimum primary mirror position?
From: Jim Simpson
Reply To: mapug@shore.net
Date: Sat Oct 14 00:12:02 1995

> Date: Fri, 13 Oct 1995 12:09:51 -0500 (CDT)
> From: Rob Robinson <robinson@sky.net>
> To: mapug@shore.net
> Cc: mapug@shore.net
> Subject: Re: Optimum primary mirror position?
> Reply-to: mapug@shore.net

> On Fri, 13 Oct 1995, Tom Mote wrote:
> > I broke down and stuck a meter stick thru my OM-1 with the adapter attached.
> > [Fear and trepidation!] The best eye ball measurement that I can make is
> > 85.5 mm +/- 1 mm from the rail that the film rides on to the table that I had
> > the end of the T-adapter was pressed against. I hope that this gets you close
> > enough for your needs.
>
> Correct me if I am wrong, but it seems like a long time ago, I saw in a
> book something about a "standard" for 35mm camera, which was the distance
> from the film plane to the front of the camera (where a lens would botton
> out). If there was a standard ( and again I don't know if there is), then
> if you had that number, it would be easy to measure from the FRONT of the
> camera forward...
> Anyone know if this is true??
>
> Rob Robinson
> Bonner Springs KS, USA
> http://www.sky.net/~robinson
>
>
Don't know if there is a standard, but according to my book on Nikon
F cameras, the film plane is 46.5 mm from the base (front) of the
lens mounting ring. According to the book, the film plane is not
marked with any special indicator, but coincides with the top line of
the serial number on the top plate of the camera. (This is for a '70
vintage Nikon F camera. Since lenses are still interchangeable, I
assume Nikon has maintained this dimension through the years.)