Re: [Leica] Re: Testing and grinding techniques at Solms

[DonjR43198@aol.com]

The following comment was made:

You should also tell the Lug membership that Leica Solms grinds lenses to an 
accuracy of 1/10,000 of a mm which I was told far surpasses any other lens 
manufacturer.

Paul T. Collura

I am not sure what is meant by "an accuracy of 1/10/000 of a mm" since that 
could be surface finish, thickness, geometry, etc.  Also, it would be helpful 
if we could convert that to inches since I am so old fashioned that inches 
and fractions thereof are more easily understood and visualized.  If one 
meter equals approximately 39.7 inches, then one millimeter must equal .0397 
of one inch (39.7" divided by 1,000 = .0397") and one-tenthousandth of one 
millimeter must equal .00000397 of one inch (.0397" divided by 10,000).  If 
we are in agreement that "1/10,000 of a mm" equals approximately 
four-millionths of one inch (.000004") , I am in full agreement that Leica is 
capable of finishing lens elements to that tolerance relative to geometry, 
finish, and thickness on a production basis, and has probably been doing so 
for many years.

My confidence still lies with the Leica lenses when one wants the finest 35 
mm image that may be captured on film and the latest generation of APO and 
Aspheric lenses has only reinforced that opinion.  Until someone comes along 
and shows by numbers or other objective criteria that the Leica glass has 
been surpassed, my 35 mm camera bags will remain stocked with Leica lenses. 

It is my recollection the famous H&W Control team were of the firm opinion 
that the Leica lenses were tops.  That was about 15 years ago but it would 
appear that Leica has continued its lens dominance and the new generation has 
solidified that position.

In an effort to keep up with the state-of-the art in lenses, I have installed 
a Durst L 1200 with point light source head and point light source condensers 
for 35 mm, 2 1/4 sq. and the current Rodagon APO lenses.  Then using Tech Pan 
and the old Willi Beutler developer formula, my neighbor's home becomes the 
test target for new lenses and Hasselblad versus Leica lenses.  Leica 
negatives are enlarged 16X and Hasselblad 8X to approximate 16X20 prints.  
Now that Leica has brought on the APO and Aspheric lenses, the quest starts 
anew.  

Are we having fun yet?