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Re: [OM] ( OM ) lens resolution capability

Subject: Re: [OM] ( OM ) lens resolution capability
From: "Norman S. Nadel" <nsnadel@xxxxxxxxx>
Date: Tue, 15 Oct 2002 17:30:01 -0700
Brian:  Many years ago I took about 3000 photomicrographs of my surgical
specimens with my OM1 mounted on my Olympus microscope. To avoid vibration,
I mounted the scope to a plywood base. The camera was mounted on to the
scope with an Olympus adapter made for this purpose.  I then built an
adjustable right angle bracket out of stainless steel (probably weighed 5
pounds) and mounted one end to the camera and the other end to the plywood
base.  When all was assembled, the unit was "one solid piece" and vibration
was eliminated. With your method I think that vibration could still be a
factor.  Unfortunately, I no longer have that bracket .. I do have the scope
and camera.

Norm

Norman S. Nadel, M.D.

----- Original Message -----
From: "Brian Swale" <bj@xxxxxxxxxxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Tuesday, October 15, 2002 11:59 AM
Subject: [OM] ( OM ) lens resolution capability


> Ho folks,
>
> Yesterday I was able to use a microscope to examine photos I took of a
> layout of Patterson Optical Test target charts using several lenses.
>
> The Olympus microscope was set up so that I could use it at total
> magnifications of 40x and 100x.
>
> The film was Fuji Velvia RVP 50 asa  E6. The camera used was an OM4Ti
> on a Manfrotto 3047 3-way head mounted on a Gitzo 320 Studex carrying
> stabilising weights totalling 20kg from its apex.
>
> I later examined the same slides using my projector putting the image onto
a
> plain-painted flat surface.
>
> To my surprise I found I could distinguish more line-pairs using the
projector
> set-up than I could using the microscope at either of the two powers. So I
> conclude that the Will-Wetzlar Maginon 2.8 projector lens is nowhere as
> deficient as I had previously thought.
>
> I now wonder if I have been quite as scrupulous at setting up the test
set-up
> as I might have been; I think there could be scope for marginal
improvement
> and will probably carry out additional tests, and probably try higher
lighting
> levels and/or electronic lighting bypassing the use of the shutter..
>
> I tested these lenses
> Zuiko 35-70 f/3.6
> Zuiko 135mm f/3.5
> Samyang 18~28 zoom
> Panagor 55mm macro capable of 1:1
> Two Zuiko 50mm f/1.8 MIJ lenses.
>
> The best of the bunch seems to be the Panagor; sharp and contrasty.
> f/11 Centre 54 l/mm Corner 60 l/mm
> f/5.6 Centre 33 l/mm Corner 48 l/mm
>
> Zuiko 135 f/3.5
> f/11 Centre 52 l/mm Corner 40 - 50 l/mm
> f/5.6 Centre 38 l/mm Corner 26 l/mm
> f/3.5 Centre 20 l/mm Corner 20 l/mm
>
> Zuiko 50mm f/1.8  MIJ
> f/11 Centre 42 - 50 l/mm Corner 50, up to 72 l/mm
> f/5.6 Centre 27 - 36 l/mm Corner 27 - 45 l/mm
>
> Samyang 18~28 @28mm
> f/11 Centre 25 - 30 l/mm Corner 20 - 24 l/mm
> f/5.6 Centre 10 - 20 l/mm Corner 20-27 l/mm
>
> @ 18mm
> f/11 Centre 20 - 33 l/mm Corner 10-27 l/mm
>
> Zuiko 35-70mm @ 70mm
> f/11 Centre 33 l/mm Corner 44 l/mm
> f/8 Centre 30 l/mm Corner 25 l/mm
> f/5.6 Centre 10-24 l/mm Corner 24 l/mm
> f/3.6 Centre 10-24 l/mm Corner 18-27 l/mm
>
> @ 50mm
> f/11 Centre 27-34 l/mm Corner 20-24 l/mm
>
> @ 35mm
> f/11 Centre 33 l/mm Corner 43-54 l/mm
>
> Clearly there seem to be some aberrations in my results - look at the
bottom
> line above, for example. So my test method needs improvement.
>
> I had hoped to find better results from my glass, I have to say.
>
> Brian
>
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>
>


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