Archived posting to the Leica Users Group, 1997/03/23

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Subject: Re: Leica Alternatives--Fogging
From: Dan Cardish <dcardish@microtec.net>
Date: Sun, 23 Mar 1997 10:55:02 -0500

At 08:55 PM 22-03-97 -0800, Stephen Gandy wrote:

[snip]

>To see it, you need a small powerful flashlight---sometimes even then
>the problem can only be seen in one direction.  So shine the light 
>through both ends of the lens to check it properly.   For lack of a
>better description, ANY light fog or smoke like effect on any of the
>elements, is what requires the cleaning and is commonly known in the
>camera business as "Fog" or "Haze."
>
>To get a better  idea of what I am talking about, take a brand new lens
>and do the light test as described.  You will see nothing but clear
>glass.  That clear glass effect is what you are looking for in ANY lens
>regardless of how old,  because if its not crystal clear------you get
>internal light reflections and loss of contrast.  
>
[snip]

I just tested my leica lenses (all modern vintage) as per above.  They all
appeared clear, though there was a tad of dust in them.  Then I tested two
Nikkor lenses, again both fairly modern, late 70's to 80s, a 50/1.4 AI and
an 85/1.4 AIS.  Both lenses exhibited a kind of fine haze when the penlight
was shone through them in a darkened room.  It is not noticed when looking
through the lens in normal lighting.  Funny thing is that they both take
very sharp high contrast images.  The 85 in particular is one of the
sharpest, highest contrast lenses that I have.  Unless the haze will lead to
permanent damage to the lens, I can't see how cleaning it would be
advantageous, unless I were planning on selling the lens to a collector who
would know to look for something like that.

Dan C.