Archived posting to the Leica Users Group, 2012/04/15

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Subject: [Leica] Possible lens adjustments
From: red735i at earthlink.net (Frank Filippone)
Date: Sun, 15 Apr 2012 15:31:18 -0700
References: <80F9701439F20347874CE5E4E03C22E95A20BA43@WHIZZMAIL02.whizz.org>

I am going to assume you got different results from different apertures, and
that manifested itself at differently at different distances...on your M9.

If my memory serves me correctly, this is a problem with this specific
lens.... ( and maybe others, I forget)  It has to do with the design.

The modified cam works based upon distance, making it more accurate at
any/all distances.  For $90, if that would fix it, it would be a bargain!

There is no aperture correction possible... maybe.....

Apparently the 75 Summicron does not suffer the same problem.  With the
prices of the Summilux being what they are, you might just be able to swap a
Summilux for a Summicron.... suffer the 1 stop loss, and come out a winner.

Ditto the Summarit, but it is slower... and a lot cheaper.... but 1 1/2
stops slower...maybe not what you were after.

Frank Filippone
Red735i at earthlink.net


Just what is possible with tweaking?

I tested my 75mm Summilux yesterday, tripod and 1.4x magnifier, at f1.4-f8
in full stops. I am more interested in the wide open focus.

It is spot on 10m to infinity.

It back focusses greatly 3m to 8m (+10cm)

It back focusses less so <3m

Will it ever focus correctly at all distances?
Will I have to choose an aperture and distance to get optimum calibration
and the rest all fit around that?

thanks

john




Replies: Reply from john at mcmaster.co.nz (John McMaster) ([Leica] Possible lens adjustments)
In reply to: Message from john at mcmaster.co.nz (John McMaster) ([Leica] Possible lens adjustments)