Archived posting to the Leica Users Group, 2005/01/26

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Subject: [Leica] adhesives
From: sethrosner at (Seth Rosner)
Date: Wed Jan 26 05:35:45 2005
References: <> <> <> <> <> <>

Feli, I think that if you shoot at full aperture where even a flawless, 
recently CLA'd DR can produce some flare, you can find a bit of "glow".


----- Original Message ----- 
From: "Feli" <>
To: "Leica Users Group" <>
Sent: Wednesday, January 26, 2005 2:26 AM
Subject: Re: [Leica] adhesives

> 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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In reply to: Message from mjblug at (Michael Blugerman) ([Leica] adhesives)
Message from s.dimitrov at (Slobodan Dimitrov) ([Leica] adhesives)
Message from rangefinder at (Didier Ludwig) ([Leica] adhesives)
Message from jbcollier at (John Collier) ([Leica] adhesives)
Message from Frank.Dernie at (Frank Dernie) ([Leica] adhesives)
Message from feli2 at (Feli) ([Leica] adhesives)