[Leica] adhesives

[feli2 at earthlink.net (Feli)]

On Jan 25, 2005, at 10:33 PM, Frank Dernie wrote:
> Adhesives are widely used in almost every engineering discipline now. 
> It is lighter and cheaper and plenty strong and accurate enough. I do 
> not agree that the recent lenses are necessarily better than older 
> because of modern machining though. They certainly no longer need 
> massively skilled technicians to assemble them, but the old stuff, 
> hand assembled, shimmed and carefully inspected during assembly should 
> all be the same as each other within similar tolerances to recently 
> lenses, it just takes more manual skill and time to achieve the same 
> level of consistency.
> That is not to say the recent designs are not optically better, my 35 
> f1.4 aspherical is comfortably the best 35mm lens I have ever used, 
> obvious even on the RD1, it is just that my experience of precision 
> mechanics shows me that it is much cheaper and less skilled to reach 
> the same level of precision nowadays than 30 years ago, but the final 
> level of precision is no greater today than then. Materials, OTOH are 
> hugely better today than then.
> Frank

I wonder how much advances in the testing equipment used during 
assembly affects the performance of vintage lenses. Anyone remember the 
spinning drum with the slots cut in to it, that Leica used to use to 
test shutter speeds...?

I recently had my Summicron DR cleaned by Leica NJ. It's always been my 
favorite and most used lens,
so I am very familiar with the results it produces.

The good news is that there is a very visible jump in performance. It 
always was a sharp lens, but this is ridiculous.
Contrast is also up by a noticeable margin. Both of these improvements 
are even more visible when shooting wide open.

The bad news is that when Leica cleaned out the haze, they also killed 
the "glow", which I loved very much. 8-(
Sometimes it glowed a little too much. If a bright lightsource was in 
just the correct spot, it would flare out the
entire frame. Seth told me that the white haze is actually oxidation 
formed by the metal in the glass, as it is exposed
to the oxygen in the air. So, it appears that old lenses ripen with 
age, like a good wine. ;-)

feli

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