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[OM] Re: 'Cheap-o Zuiko? Or Leitz?

Subject: [OM] Re: 'Cheap-o Zuiko? Or Leitz?
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxx>
Date: Wed, 20 Sep 2006 06:17:05 -0400
But it's not so random as you make it sound.  The major distinction is 
whether the test was conducted on a body that allows mirror and aperture 
pre-fire with self-timer.  The mirror flipping up is one source of 
vibration but just as troublesome or more so is the kick of the aperture 
lever closing down the lens.  Unless both of these vibration sources are 
under control you're not getting a real test of the optical performance 
of the lens.  Not included in any of Gary's testing was something to 
control shutter vibration.  We don't know how the results might have 
differed if he draped one of Walt's bean bags full of lead shot over 
camera and lens.

Sometimes there are significant differences between very early and very 
late models of a lens and ususally minor differences between two 
different samples of the same lens.  The grading is very strict.  I 
don't think most people would notice sample variations... unless they're 
testing lenses.  :-)

Chuck Norcutt

keith_w wrote:
> Chuck Norcutt wrote:
> 
>>I think the distinction we're talking about is not multicoating but the 
>>optical performance of the lens which changed through the years as 
>>Olympus made various engineering modifications.
>>
>>Multicoating is just one of the modifications and doesn't mean the same 
>>thing for all lenses or all versions of the same lens.  Two different 
>>versions of the same lens known to be multicoated may have different 
>>types of multicoating and may have different numbers of their elements 
>>multicoated.  Some elements may be single coated even on a lens marked 
>>as multicoated.
>>
>>Most of this stems from Gary Reese's extensive testing of Zuiko (and 
>>other) lenses.  Gary often tested multiple samples and versions of the 
>>same lens.  When interpreting these test results you also need to be 
>>aware of the body used and any other supplemental support on long teles. 
>>  The Zuiko 200/4 is especially prone to vibration but is an excellent 
>>performer if suitably restrained.  Vibration is a signficant factor in 
>>all of these tests and best results are typically reported using a body 
>>that allows mirror and aperture pre-fire with the self-timer.  Gary 
>>clearly proved that just locking up the mirror ala OM-1 isn't good 
>>enough for critical testing of lens quality.
>>
>><http://members.aol.com/olympusom/lenstests/default.htm>
>>
>>Chuck Norcutt
> 
> 
> Interesting comments, Chuck...
> 
> After I spent a good bit of time looking over Gary's site, trying to absorb 
> as 
> much of it as possible, all i was left with was shaking my head, and 
> realizing 
> that "lens tests" are only as good as the paper they're written on, and at 
> that time of day!  :-(
> 
> I'd find a lens that performed exceptionally well on, say, an OM-2. Then I 
> checked the performance on an OM-1. Deteriorated in an instant! Awful 
> performance, just by changing lens serial numbers, or camera bodies, or 
> locking up a mirror ~ or NOT locking up the mirror!
> 
> In other words, the results of any given test are good under those specific 
> conditions ONLY. Put the same lens on YOUR camera, and all bets are off.
> Might be just fine for you, or bear no resemblance to anyone else's testing 
> results.
> 
> Finding the "truth" about lens performance is a study in frustration...  <wry 
> smile>
> 
> keith whaley
> 
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