Archived posting to the Leica Users Group, 1996/09/13

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To: leica-users@mejac.palo-alto.ca.us
Subject: Re: lens flare
From: dlevy@worldy.com
Date: Fri, 13 Sep 1996 21:24:04 -0400

At 08:52  13/09/96 -0600, you wrote:
>>My experience is that lenses may suffer more flare at small apertures, not
>>large
>>ones. If the principal cause of flare is internal reflections, and these are
>>more likely to come from metal than glass surfaces (due to modern coating
>>techniques) then it follows that the conditions for flare are least at maximum
>>aperture (when there is little or no intrusion by the iris) and most at small
>>apertures. Certainly my 35 1.4 Summilux-M ASPH can give flare under certain
>>circumstances at f/8 down, whereas I've never seen the phenomenon at f/1.4.
>
>The theory of flare at small aperatures is fine, except the metal parts are
>coated (or painted) with
>anti-reflective materials also. There are too many variables, such as
>subject (reflective %), radius curve of inner elements and air space depth,
>and many more. My theory is, if the lens in question makes a good image
>then keep it.
>
>John
>
>
I haeve followed this thread for some short time and would like to just like
to say that my Summicron-C doesn't exhibit flare unless I try to purposely
induce it. Possibly, part of the problem is that as Leica users you try to
push the lenses beyond their design envelope where most users of other makes
don't attempt it. I have always considered the Leica the "Rolls Royce" of
cameras, but maybe I should rethink the analogy to possibly Maserati. Any
way, I use other brands besides Leica and it outshines them all. Oh, by the
way, if you think you got problems, head over to the Minolta group where
they're discussing the Sigma lens which has the front element falling out on
their owners. It seems it makes a great paper weight shortly after purchase. 
Brian Levy, J.D.
Toronto, Ont.
dlevy@worldy.com