Gary, it is great to hear the superb performance of Zuiko 180/2.8 -
one of my most favorite lens. I'm more than satisfy with over 70 lp/mm
resolution, may be the Tamron have over 80 lp/mm but I won't care as I
shot mostly hand held, I don't even expected I can get the max
resolution from the Zuiko (although I consistently found this lens has
better resolution then many other zuikos), but chroma is quite a big
problem of it though. Anyway resolution and sharpness is not the only
item to concern, color, contrast (to me not the higher the better) and
distortion are also very important, the Zuiko 180/2.8 just has all the
things I needed. But the best thing I can immediately see about the
Tamron is the IF design, it provide fast and easier focusing.
Concerning the shutter vibration, it could be a problem, I will check
again with my 90/2 and 100/2 to see if I was wrong about their
resolution comparison.
C.H.Ling
Gary Reese wrote:
>
> OK Alan, I responded to the Photo.net discussion, as follows
> ****************
>
> I very recently tested one in the early 101,xxx range and have some high
> contrast resolution data at 1:41 magnification using Fujichrome 64T Type
> II film:
> f/2.8: 73 lp/mm center, 65 lp/mm
> f/4: 73, 65
> f/5.6: 73, 65
> f/8: 65, 51
> f/11: 65, 57
> f/16: 57, 51
> f/22: 51, 45
>
> These data, as well as my tests of a 180mm f/2.8 with and without 1.4X-A
> teleconverter ( at
> http://members.aol.com/olympusom/lenstests/default.htm ) are in
> disagreement with the Modern Photography tests of 7/79 ( transcribed at
> http://brashear.phys.appstate.edu/lhawkins/photo/mp-zuiko-tests.txt ).
> It is my opinion that the Modern Photography tests suffered from the
> same auto diaphragm vibrations that plagued many of my tests using an
> OM-1 with mirror lockup. It wasn't until I started testing with the
> self-timer activated - thus getting mirror and aperture "prefire" - that
> I was able to control this poorly documentated source of vibration. The
> 180-200mm Zuikos are especially prone to it.
>
> Unfortunately, I never got a sample to test of the Tamron SP 180mm
> f/2.5 I'm now out of Fujichrome 64T Type I film, so any further SQF
> testing is dependent on some showing up in old stock sales.
>
> Modern Photography reported chromatic aberration in the Tamron 180mm
> f/2.5 (tested 6/86), as to be expected from a non-apo design.
>
> Gary Reese
>
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