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[OM] Re: A couple of Velvia 50 birds

Subject: [OM] Re: A couple of Velvia 50 birds
From: "C.H.Ling" <ch_photo@xxxxxxxxxxxxx>
Date: Sat, 7 Jun 2008 19:07:04 +0800
----- Original Message ----- 
From: "Moose" <olymoose@xxxxxxxxx>

> C.H.Ling wrote:
>> From: "Moose" <olymoose@xxxxxxxxx

>
> The 200/4 is tested with the Bogen support. By Gary's significant
> difference standards, these lenses are almost identical in ratings. At
> least according to these rather careful tests, the 200/4 is the equal of
> the others except for the 100/2 at f4, two stops down for the 100 and
> wide open for the 200.
>
> You can see significant appearing sample variation between the two
> 180/2.8 samples. How much sample variation affected the Modern tests and
> your experience with your 200/4, I can't know. I do know that vibration
> control made a huge difference in performance of the 200/4 in Gary's 
> tests.
>

OM 200/4 vibration problem is mainly due to aperture stop down lever, the 
problem should not exist on E-1 and shutter vibration is not as critical.

It seems not sample variation for 180/2.8 in Gary's test, I see different 
cameras were used. If you believe about sample variation then we can forget 
about all data.

> Gary's test showed the 200/4 with 2XA, OM-4 with mirror/aperture prefire
> and  lens support to be quite decent, on a par with the 180/2.8 and 2XA.
>

180/2.8 was not design to be used with 2XA.

>>  and only used once or twice in E-1, it was ok but not as sharp as other 
>> Zuikos.
>>
> This is a very interesting area. Have you read the dpreview tests of the
> Canon and Nikon 70-200/2.8 lenses?  VERY different results. The Canon
> wins for FF, the Nikon for APS size sensor. Comparing lenses across
> formats apparently isn't as easy as one might think. Results of the
> 200/4 on 4/3 format may or may not mean much for performance on FF film.
>

My experience was based on the same sensor (E-1/E-3) so APS vs FF does not 
apply.

> I'm not saying your experience isn't true, but that someone else, in
> highly controlled tests, had different experiences.
>

I belive Modern Photography Tests were also performed under well controlled 
condition. You can found the test results in Lee Hawkins' Olympus FAQ:

http://brashear.phys.appstate.edu/lhawkins/photo/mp-zuiko-tests.txt

Sharpness and resolution can be very different, if you are not using 
resolution chart you may only get an impression on the lens sharpness but 
not true resolution.

C.H.Ling

> Moose
>


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