on 9/5/02 2:43 AM, derek fong at olympus@xxxxxxxxxxxxx wrote:
> And just to keep this message (somewhat) on-topic, just got my first
> set of color photos back, which were taken with my OM-2 and my 50/1.8
> (single-coated with some dust inside the lens). The photos are crystal
> clear. You'd never think there was dust in the lens. (Previously, I'd
> always loaded the camera up with Ilford HP-5 Plus so I never even gave
> the dust a second thought since this film tends to be pretty grainy
> anyway.) This bodes well for me because a lens I bought off eBay has a
> couple of small black specks in it and I haven't gotten my test shots
> back yet, so it's a nervous wait to see if the lens will have to be
> returned...
>
> -f
>
>
> --
> Derek Fong
> Web Application Developer
> subtitle designs inc. <http://www.subtitled.com/>
Not to stray from the subject and back into camera/photography stuff, <g>
but I'll comment that you would be amazed at the stuff that doesn't matter
in a lens... I discovered that a camera that takes very good pictures had
some fungus in the lens. I cleaned it out, but I can't really see any
difference in the resulting pictures. This would be different if I were
making 12X enlargements, or projecting slides 60" wide... but for my 4x6"
prints and scans onto the computer the cleaner lens is not noticably
different. I've taken shots with fingerprints on the front element of a
lens, not noticing until it was too late, and then found that they really
didn't impact the picture.
A while back I got a Zuiko 24-Shift lens, which had a big (well, it seemed
BIG to me...) scratch on the front element. This scratched area was about
5/8" length, about 1/16" to 3/32" width and noticably deep into the glass...
Viewing the front element head on, mounted on camera, the scratch would have
been at about 7:00 to 8:00 area of the element about 1/3 way in from the
edge, so significantly in the main area of the element. As I knew I was
going to have the lens repaired, I shot a roll of film to see what impact
the scratches would have... I was surprised to find that the effect was to
soften and blur the detail in the image only in a small area in the lower
left corner of the image. Relative to the full frame, the blurred area was
about 1/32 of the full frame area. Based on the size of that scratch and its
relative effect, I would say that a minor scratch or a speck of dust or dirt
would have such a miniscule effect that you couldn't spot it unless you
actively searched for the flaw. I tested the lens again with the same photos
location and setup, after Olympus Japan repaired it, and it was (of course)
perfect :-)
--
Jim Brokaw
OM-1's, -2's, -4's, (no -3's yet) and no OM-oney...
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