[Leica] Lens Accurization for the Perfectionist

[Leikon35 <Leikon35@aol.com>]

 In a message dated 98-04-15 16:47:32 EDT, Harold Gess wrote:
<< snip  <<
 I took the back doors off my various Leica M's and mounted them on a tripod,
 & took the plain ground glass ---------
   >> ===============================================

 Those of you that are seriously into fine tuning guns will know immediately
 what I am talking about but for the rest of you Leicaphiles, bare with me.

 All early Leica cameras had problems in matching a lens to its body, since
 the actual focal lengths varied ie (+ or - 1/10mm) and the bottom shells, not
 being die cast also varied.  The solution to this, in the late '20s & early
'30s
 was to have a PEEP HOLE built into the back of the camera where a loupe
 was attached ( quite similar to what Harold has just done) but since they
 were focusing on the aerial image rather than a ground glass, it was more
 accurate. After adjustments by adding shims ( .001/mm ) to the lens flange
 the peep hole was plugged and the pressure plate revolved to make it light
 tight.  My exact figures might be off a tad but believe me - they were thin.

 When I worked professionally with Leicas back in the "50s to '70s, serious
 35mm still photographers sent their Leica to Mel Pierce to have the lenses
 matched to the bodies.  Although this really wasnt necessary after the die-
 cast bodies were made to closer tolerances, the lenses still had a variance
 in focal lengths.  You can still see the # 0-9 stamped on many lenses - but
 that is another story already fully covered on the LUG last year.

 Even today, you will read about recommendations to have your high -speed
 lenses ( particularily the Noctilux)  matched to your individual camera. 

 I think it was either Browning or Winchester that got the idea of speeding up
 production by making closer tolerance parts that could then be interchanged.
 In my days of racing Porsches, an overhaul after each race was not unusual
 and the pistons & cylinders were graded in groups by 1/10,000" differences;
 the pluses balancing the minuses.

 Marvin (the infamous D.Gonzalez reference) Moss