Archived posting to the Leica Users Group, 1999/06/18

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Subject: Re: [Leica] Heliar impressions
From: InfinityDT@aol.com
Date: Fri, 18 Jun 1999 16:13:02 EDT

In a message dated 6/18/99 3:58:49 PM Eastern Daylight Time, 
dmorton@journalist.co.uk writes:

<< Not sure where f16 came in WRT the Contax-mount Hologon, but that lens is 
 f8, that's all, fixed, so f8 is both the maximum and minimum aperture of 
 the Contax mount Hologon lens. >>

I remember someone telling me that the Hologon vignettes so much that a 
graduated filter with a darker center fading to a clear outside is required 
to even out the light falloff.  If the edge falloff is 2 stops (f16) the 
filter would need to bring the center to f16 as well.  This is just hearsay, 
but it makes sense except that I've used the 15 f5.6 and later f3.5 Nikkors 
and they vignette some, but I never measured it at anywhere near 2 stops.  
Can't imagine the Nikkors could be better than Zeiss ; )


DT