Archived posting to the Leica Users Group, 2001/05/09

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Subject: RE: [Leica] Konica facts
From: leica@davidmorton.org
Date: Wed, 9 May 2001 19:06:35 +0100

Stephen Gandy wrote (in part):

"According to a friend of mine who works as a consultant with Konica, the
problem is not so much an intentionally chosen different back focus, but how
the in some cameras the COMBINATION of individual tolerances of different
parts can COMBINE to unacceptable levels, ie a combination of parts all with
the larger tolerances will combine to make too large a total tolerance.
This is another way of describing the mechanical tolerance issue you make
note of.

He told me that not only is Konica Japan is aware of the problem, but they
are taking in cameras to be adjusted to Leica M tolerances and adjusting
them for free.  I emailed Konica USA on this several weeks ago, and got the
same response from them that I got in February after Akhil's post --
nothing."

IF Erwin's figures are correct then there simply *isn't* any way to adjust
the Konica body such that it will be within tolerances for *both* Leica
lenses and Konica lenses.

Erwin says "The back focus of the Hexar RF is 28.00mm with a tolerance
bandwidth of 0.06mm" so the tolerance limits of the Konica back focus (for
both bodies and lenses) are 27.94mm to 28.06mm. He goes on to say that
"Leica data are: 27.80mm with a max tolerance of 0.02mm" so the Leica
tolerance range is 27.78mm to 27.82mm.

Notice that those two ranges do *not* overlap.

If these figures are accurate, then you could adjust a Konica body to work
with Leica lenses, but it would then be out of spec for Konica's own lenses.
Likewise a Konica adjusted to work with Konica lenses will be out of spec
for Leica lenses.