[Leica] adhesives

[jbcollier at shaw.ca (John Collier)]

In the old days it was impossible to make precise enough lens mounts. 
Every element had to be hand fitted, shimmed and centered. Glue would 
be a foolish attachment method as the likelihood of making mistakes was 
very high. In short there was a good chance you might have to take it 
back apart to get it right.

Now machining precision is phenomenally accurate. This eliminates the 
costly hand fitting. If you compare the lens schematics of the old and 
new 50/1.4s (non-Asph) you will see what I mean. Same formulation but 
the newer glass has precision mounting surfaces.

This means that we get smaller sample variation and generally better 
overall performance as the manufactured lens is much closer to the 
ideal.

I do not mind that my lenses have to be heated to be disassembled. I am 
just so d***ed impressed with their performance I don't care!

John Collier
(who has on occasion lost in the sample variation game with older 
lenses)

On 25-Jan-05, at 12:20 PM, Didier Ludwig wrote:

> Slobodan's concern is justified, IMO. As it was presumably me starting 
> the thread about glued lenses and heating them, I can only repeat what 
> the Leica specialist from Karl Ziegler Fototechnik, a reputed camera 
> and lens repair company near Zurich, told me: Most, if not all, of the 
> newly designed Leica lenses have more or less glued parts or blocks 
> inside. It allows smaller and lighter constructions and lowers the 
> engineering and production costs significantly; but raises the repair 
> costs on the other side. This is, economically seen, good for Leica, 
> but bad for us as soon as we have a lens to repair. ALL new japanese 
> lenses were made like that, too, he said, manual and AF. It's just the 
> way how lenses are manufactured these days, whether in Europe or in 
> Japan.
>
> Thats why I'd say, don't trade in your old pre-ASPH's for the new 
> ones, as they might survive them :-)
> Didier