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Re: [OM] ( OM ) Zoom lens adjustments.

Subject: Re: [OM] ( OM ) Zoom lens adjustments.
From: clintonr@xxxxxxxxxxxxxxxx
Date: Sun, 19 May 2002 13:27:43 -0500
Brian Swale wrote:
> 
> First, the DOF button does not engage the DOF mechanism until it is part-
> way in, so pressing the DOF button does not stop the lens down to the full
> aperture that it is set at.

Maybe the lever inside the mount is bent -- it's got a narrow spot where
than can happen.

> 
> Second, the focus mechanism does not focus exactly on infinity when it is
> turned over to the infinity mark; it goes quite some way past. This varies
> depending on the zoom distance selected.

Yep, it's probably out of adjustment.  That or loose elements, loose/bad
rollers, etc.  The 3.6 is rather difficult to focus.  Under the zoom
grip are two sets of adjustments -- one changes infinity at tele, the
other adjusts focus during the zoom.  You've got to set one, then adjust
the other, then go back to the first, etc., until the focus is good from
tele to wide.  If you're more than moderately insane (you gotta be a
little "off" since you're on the oly-list, right? ;^), I'll describe the
steps involved -- just ask.

> 
> Third, as the zoom distance is altered, the selected focus alters. It is
> supposed to stay constant.
> 

Could be things are loose inside, or just out of adjustment, or parts
are "rubbing" causing them to move (in order of likelihood).  Hopefully
just fixing the focus will correct the problem.


> My 2 questions; is the DOF fixable so that it pushes the aperture levers all
> the way; and

Yes -- hopefully, if it can be straightened properly...

> 
> are the two focus problems fixable, and how long would it take a skilled
> person?
> 

If I'm lucky, really lucky, I can set focus in about 2 minutes.  But
being lucky with a 3.6 is rare -- figure about 10 minutes most times. 
But that's after everything else has been "fixed" and checked -- loose
elements, barrel damage, bad rollers, etc. -- that may take anywhere
from an hour or two, or more (more if I've got to open the ball bearing
races -- yuck!  376 tiny bearings, bouncing across the floor... ;^). 
The "average bear"?  Plan on at least half an hour to set the focus
_well_, several hours to "fix" it first, unless the bearings get loose
-- then maybe a day or two!

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