[Leica] M6 rangefinder accuracy limit & 90/f2 ASHP

[jsaravia@zeus.uniandes.edu.co]

Hi Lugers:

I have this table from an old mail, not sure about who post it... It was you
Erwin ????, sorry if  I am wrong.
- -----------

There is a mechanical/optical relationship between the accuracy of the
rangefinder and the baselength in relation to the maximum aperture/.
The equation will be published elsewhere, but here is the result:

Focal length    Max aperture    Max aperture
                M3              M2, M4, M5, M6
21 mm           0.12            0.15
28 mm           0.21            0.26
35 mm           0.33            0.41
50 mm           0.67            0.84
75 mm           1.5             1.88
90 mm           2.17            2.71
135 mm          4.88            6.1

- ----------

According with that,  the new 90/f2.0 could reach all its preformance (hard
to focus ok) when used on a 0,75 M6, or even a M6 0,85 (what about the new
135mm/3.4),  I have read that even the 75 f/1.4 is hard to focus.

I use my Noctilux alot and have never had problems with it, I have the
80/1.4 and like it very much, I am thinking seriously about the 90/2.0 ASHP
(I may trade the 80/1.4) but, if when used at f/2.0 it is beyond the M6
rangefinder accuracy limit, is it worth buying it ? , should I go for the
elmarit ?...... I am confused....

Any Comments????

Thanks in advance

Jorge Saravia