At 2:07 PM +0000 7/10/03, olympus-digest wrote:
>Date: Thu, 10 Jul 2003 00:52:52 -0700
>From: Moose <olymoose@xxxxxxxxxxxxx>
>Subject: Re: [OM] Infinity Focus problem - 55mm f1.2
>
>Consider also the possibility that your mirror is out of adjustment
>before taking a lens apart. If you have different bodies, check it out
>on them. Check out other lenses on the same body with the 2.5x. I bought
>a zoom a while ago and was checking it out when I discovered that it
>wouldn't focus to infinity at the wide end. I was getting all wound up
>about all the hassle of a return, but then thought to check it out on
>another body and vice versa. I had one body with the mirror out of
>adjustment. Remember the critical focal distance is lens to film and the
>viewfinder has to be adjusted to that.
There is a direct test as well.
1. Put the camera on a tripod and take the back off the body. Tape a piece of
thin frosted glass down in place of the film, frosted side towards the lens.
Set lens wide enough to make focusing critical, to f/1.2 or f/2.
2. Focus on distant trees using the viewfinder. Mark the location. This is
most accurately done by putting a piece of white paper sticky tape on the lens
barrel and marking the position of something on the focus ring on the white
tape. (Tape adhesive can be removed using a Q-tip dampened with lighter fluid.)
3. Using a lockable shutter release, put the camera in B shutter mode, leaving
the mirror up and the shutter open.
4. Then, using a hand magnifier as an aid, see if the image on the ground
glass is in focus. If you have the readjust the lens to achieve best focus,
the camera body is out of adjustment. In particular, the mirror or focus
screen isn't where it should be. Fixing this often requires a CLA.
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 >
|