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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