Ian,
At 4:31 PM +0000 1/24/02, olympus-digest wrote:
>Date: Thu, 24 Jan 2002 09:31:11 +0000 (GMT)
>From: "Ian A. Nichols" <I.A.Nichols@xxxxxxxxxxxxx>
>Subject: [OM] Checking Focus accuracy, was: OM lens fascination 1
>
> > One can test this at home:
> >
> > 1. Buy a small piece of thin finely-frosted ground glass. I got mine
> > by mail order from Edmund Scientific
> > (<http://www.scientificsonline.com/Scientifics/>) some years ago.
> > Using a glass cutter and steel ruler, cut the glass into a strip 35mm
> > wide and perhaps 70mm long. With 220-grit wet-dry sandpaper face up
> > and wetted on a large sheet of glass, grind the cut edges of the
> > ground glass straight, and smooth any sharp edges or corners off.
>
>Or you can just use that spare 1-13 focus screen. Or any other focus
>screen. Just fix it in place over the film gate, matte side towards the
>lens. You'll have to turn it slightly diagonally so the corners rest on
>the inner film rails and hold it in place with rubber bands and
>something to pad out the space between the bands and the screen.
>
>I've used this method successfully to check & adjust the rangefinder on
>my 35RD and it should work with an OM too.
I don't see why this wouldn't work either, although I would be afraid of
damaging the focus screen, which is made of plastic (polystyrene?) and thus has
delicate surfaces. If one has a beater screen, then no problem. The ground
glass I used cost something loke $5.00 for a 6x6" piece ten years ago.
Joe Gwinn
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|