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Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcc3!sdcc6!ix654
From: ix654@sdcc6.UUCP ({)
Newsgroups: net.rec.photo
Subject: Re: Camera Vibration and Sharpness
Message-ID: <1968@sdcc6.UUCP>
Date: Sun, 17-Mar-85 19:24:26 EST
Article-I.D.: sdcc6.1968
Posted: Sun Mar 17 19:24:26 1985
Date-Received: Tue, 19-Mar-85 04:28:28 EST
Organization: U.C. San Diego, Academic Computer Center
Lines: 33

>The OM-1 and (I think) The OM-2 have a handy mirror lock up lever on the
>right hand side of the lens mount, opposite the PC connector for the
>flash.  The OM-3's & 4's seem to have lost it in the race to
>modernization.
>{ucbvax, decvax}!mtxinu \
>           ihnp4!amdahl / !rtech!daveb

    No, OM-2 has no mirror lock-up. Newer models (OM-2S, 3, 4) use
the self-timer trick that someone mentioned in a related article. 


>.....  about 75% of the print--mainly the center--was sharp; but
>the corners were blurry, thus ruining what otherwise was a really
>good photo.  I've heard explanations that the enlarger lens was
>faulty; and I've heard that's impossible in a good commericial
>shop.  Anyone have any experience with this?
>Ken Wolman
>Bell Communications Research @ Livingston, NJ
>lcuxc!kenw

    If the slides are not glass-mounted, then they are never
completely flat, so if the enlarger is focused on the center - the
edges may be blurred. If I understand the principle behind depth of
field correctly, this can be minimized by stopping the lens down (it
should work "backwards", i.e. not only in cameras). But that means
longer exposure times and I have yet to find a commercial lab that
would be willing to slow down their tempo for the sake of their
demanding clients (maybe .001 % ?) By the way, my experiences with
processing labs, excluding Kodak, are disastrous, and I would like
to hear some comments about that from other people. 

                                      E.J. Behr, UCSD
                                       (sdcc6!ix654)