Archived posting to the Leica Users Group, 2000/12/22

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Subject: [Leica] Calibration
From: "Erwin Puts" <imxputs@knoware.nl>
Date: Fri, 22 Dec 2000 12:03:16 +0100
References: <200012220204.SAA00609@mejac.palo-alto.ca.us>

Frank wrote in part:
>Erwin, in these days of vertical RF adjustment being off on a brand new
>camera, I think that all new Leica buys needs to be checked.  We can not
>assume they are correct direct from the factory.

I disagree. First of all, the vertical misalignment is inconsequential as
far as RF accuracy is concerned. Mind you: it is not OK, but more of
nuisance than a functional error. This is another myth. The vertical
alignment has no relation to the RF accuracy.
If your lens focusing five feet beyond your implied plane of focus, than
there is someting rotten in the state of Denmark (free from Shakespeare).
Then of course a check of the lens/body combo is in order.
My remarks were related to the proposition that the Noct or the 1.4/50 or
1.4/75 needed specific (lens related) adjustments, which is not correct.
The bayonet flange is machined to an accuracy of 1/100mm, the RF cam has a
tolerance of 1/100mm too  and the lens is adjusted to get maximum contrast
at 30 lp/mm. These  measures ensure exact focus with any lens/body
combination. Of course a failure like yours is a bad instance of missing QC
for your lens.
I would without any doubt accept,  that the bodies/lenses as delivered  from
the factory are within specs. And your proposal that we need to check every
lens/body combination is several bridges too far.
To infer from a few bad examples that the state of Leica quality is below
any reasonable industry norm is untenable. If Leica cannot hold a machine
tolerance of 1/100 mm in general, they should close the doors immediately!

Erwin