Archived posting to the Leica Users Group, 2002/05/21

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Subject: Re: [Leica] Re: Update to the Hexar/Leica back focus test
From: Paul Chefurka <paul@chefurka.com>
Date: Tue, 21 May 2002 09:57:33 -0400
References: <200205191615.g4JGFnN15795@panix3.panix.com> <009201c1ff55$583bc660$f77b7ad5@desktop> <lvmfeugokd9cv0mrtmtf5nltrcvb49cbj1@4ax.com> <0ohkeuocoh09c7r2ahij4i810rgr7ptjv7@4ax.com>

On Tue, 21 May 2002 08:15:00 -0500, "Eric" <ericm@pobox.com> wrote:

>Paul:
>
>>I tightened up my procedures and picked a section of the neg closer to
>>infinity to examine.  Lo and behold - there's just no dang difference.
>>
>>http://www.chefurka.com/Misc/BackFocus.html
>
>I'm not interested in disputing your results.  I really don't care if there
>is a difference.  Many people in real life seem to get great performance
>with the Hexar + Leica lenses.  Only way to know for sure is to try it for
>yourself.
>
>I would dispute your conclusion that this closes the case.  There are too
>many variables.  It could be that your rangefinder or rangefinders are
>slightly out of alignment.  Could be that your way of focusing favors the
>Hexar slightly.  Could also be that the Hexar is superior and your focusing
>favors the Leica, making them both look similar.  :)

That's why I did the test at infinity - at least that takes focussing
technique and the RF mechanism out of the equation.  I should have
qualified my statement - this closes the case for me, using my cameras and
that particular lens.

>That's my main objection to a "test" like this.  If it's not scientific, it
>doesn't really answer anything for other people.  Only for the tester.
>Everybody's technique is slightly different.

The only way to answer the question for everybody is to test a
statistically significant sample of cameras using an accepted valid
technique involving only that single variable.  That ain't going to happen
in user-land.  So all we have to go on is the accumulation of anecdotal
reports.  Mine is just one of those data points, nothing more or less.

>If they look fine on the light table, I wouldn't worry about trying to
>measure something that's so hard to measure.  :)

That's my feeling exactly.  Frankly, where the Hexar is concerned, I'm much
more annoyed by the quality of the finder, the shutter delay and the
misloads I keep getting than by any possible back focus problem.

Paul

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In reply to: Message from "Rei Shinozuka" <shino@panix.com> (Re: [Leica] Try again)
Message from "geebeespaw" <geebeespaw@btopenworld.com> (Re: [Leica] Try again)
Message from Paul Chefurka <paul@chefurka.com> ([Leica] Update to the Hexar/Leica back focus test)
Message from "Eric" <ericm@pobox.com> ([Leica] Re: Update to the Hexar/Leica back focus test)