Archived posting to the Leica Users Group, 1998/02/19

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Subject: [Leica] RE: 35 f/2 ASPH w/built in star filter
From: "BIRKEY, DUANE" <dbirkey@hcjb.org.ec>
Date: Thu, 19 Feb 1998 11:00:47 -0500

My slides show an 8 point star, which incidently corresponds to the 8 
pins and 8 notch guides used for the 8 aperture blades.  
I think I've discovered the problem upon closer inspection......   you 
can move the aperture ring slightly beyond f/2.  When you do that you 
will notice that aperture blades retract slightly more causing the 
points of the pin guides to enter the aperture ever so slightly with a 
sufficiently small gap to cause a starburst/star filter effect.  You 
can get the sunburst effect with any lens when you place the sun behind 
something that has a small effective opening.  Galen Rowell does it a 
lot.

It appears that if you move the aperture ring back to the f/2 click it 
disappears.  I haven't tested both to confirm this on film but it 
checks out visibly.  Leica has inadvertently given us a star filter 
than can be turned on or off.......   

Now that's German engineering.........  

Now I can sleep better.

Duane Birkey
HCJB World Radio
Quito Ecuador