I checked my lenses on my OM-2 (calibrated for a 2 screen) with a Kyoritsu
EF 8000 tester and found:
24mm f2 +- 0
35mm f2 +- 0
50mm f1.8 +- 0
50mm f2 macro +- 0
85mm f2 +- 0
100mm f2.8 + 1/4 stop
180mm f2.8 + 2/3 stop.
The error probably is directly related to how the 2 series screen is etched
to straighten the light rays to make it appear brighter, but then not enough
of those rays strike the cds cells on either side of the eyepiece lens. I
rechecked these lenses with same body with +2/3 dialed in and a plain 1-13
screen in
place and found no error with the 100 or 180. If folks want to use Beattie
or series 2 screens in the OM-1 thru 2N they will have to accept this.
People
can keep it in mind when shooting slides with longer lenses. Won't matter
much with negative film.
_________________________________
John Hermanson www.zuiko.com
Camtech, Olympus Sales & Service since 1977
21 South Lane, Huntington NY 11743-4714
631-424-2121 For Free Olympus manuals,
please call 1-800-221-3000
_________________________________
----- Original Message -----
From: "Winsor Crosby" <wincros@xxxxxxxxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Friday, July 19, 2002 9:22 PM
Subject: Re: [OM] are SC lenses to blame?
>John H. and I have had a frustrating time with a couple OM-1 bodies and
>meter accuracy. He mentioned that others on the list have had problems
>with certain lenses and the accuracy of the OM-1 meter.
>
>With the lenses that I have available, it seems that the SC lenses are
>the ones giving me grief. Using an evenly lit surface, the meter
>inaccuracies are as follows:
>
>21/3.5 (MC) meter is right on - agrees with hand held meter
>35 shift (SC) 1.5 stops over - this is after I let the meter "settle"
>85/2 (MC) meter is right on
>135/2.8 (SC) meter is about 1 stop over.
>
>I still need to go home and check this with my other lenses, but thus
>far is there anything mechanically different between older and newer
>versions of these lenses that would cause this? I have not had any
>problems with these lenses and the -4Ti, so I am guessing it might be
>more with the OM-1 meter, and not the lenses.
>
>Any and all information is greatly appreciated.
>
>Bob Gries
Well, it does appear that the multi coatings are doing their job.
Who said that multicoating is just marketing? ;-)
Seriously, that is strange. Could the meter sensor be misoriented and
reading a corner of the screen instead of the center or something
like that? Maybe it is picking up lens light fall off at the edge of
the field.
--
Winsor Crosby
Long Beach, California
.
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