Archived posting to the Leica Users Group, 2021/07/02

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Subject: Re: [Leica] impurities in lens
From: "A.H.SCHMIDT" <horsts@primus.com.au>
Date: Fri, 02 Jul 2021 22:37:38 +1000
References: <B580F9EB.AA9D%chrislee@mac.com> <003301bfe209$a45ffb80$131110ac@zoomtel.com>

Craig Roberts wrote:

> "How can a bubble in a lens improve image quality?" - Chris
>
> It can't.  It doesn't.  It's a myth (according to Leitz optical engineers).
> It just doesn't hurt anything.
>
> Craig
> Boston

Craig,

 the reason for the "Bubble mystique' stems from the early days of lens
manufacturing.

Some of the special glasses used in high quality lenses where very expensive.
they where used even if bubbles where present, as long as the amount  and the
size where kept within
reason. If this was the case, the did not do any harm. Bubbles in a quality
lens meant that they used high quality glasses, which where top expensive to
throw away. That's all.
There is no real reason, why a modern lens today should have any bubbles. The
process
to make glasses for lenses today insure a complete bubble free glass in most
cases.

dust or dirt particles should not be present in any new lens. If foreign
materials are found in between the lens elements, then the manufacturing
method's ate not up to standard and neither is the QA department.

In older lenses, it is possible to find some (mostly black) minute particles
mainly around the region of the lens where the diaphragm is located.
This  can be flakes of dried black paint, from the inside of the lens mounting,
or grease particles from the diaphragm. They are easily cleaned by a competent
camera repair man.

Regards, Horst Schmidt

Replies: Reply from eve <dkhong@pacific.net.sg> (Re: [Leica] impurities in lens)
In reply to: Message from Chris Lee <chrislee@mac.com> (Re: [Leica] impurities in lens)
Message from "Craig Roberts" <croberts@zoomtel.com> (Re: [Leica] impurities in lens)