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: focalpt@ecentral.com (John Van Stelten)
Date: Fri, 13 Sep 1996 08:52:22 -0600

>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



Replies: Reply from "joe b." <joe-b@dircon.co.uk> (Re: lens flare)