Archived posting to the Leica Users Group, 1998/11/13

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Subject: Re: [Leica] Early Summitar
From: Walter S Delesandri <walt@jove.acs.unt.edu>
Date: Fri, 13 Nov 1998 19:43:45 -0600 (CST)

Hello, Bill, others,

The early lenses, from many manufacturers, had many more diaphragm 
blades than later lenses.  As you note, it makes nearly a perfect 
circle.

As for the "out of focus" parts of the picture, I doubt you can see 
the difference.  HOWEVER< with light sources in the picture, you
will!  Instead of the eight pointed (most later RF lenses) or six 
pointed "flare stars" around the light sources, you will see a 
"halo" effect, more perfectly round.

As a side note, most SLR lenses have far fewer blades (Nikon-usually 
six) because they produce less drag on the auto-diaphragm mechanisms.
Also, most if not all SLR blades are single ended, kinda like shutter 
blades.  They have a "fixed" pin and a "moving" pin on the same end, 
again like shutter blades.  Most non-auto lenses (RF, View, etc)
have a pin in each end of the blade, and more blades.  

Had a photo instructor once many years ago that called these flare
star effects "light patterns" and gave an assignment to try and 
produce them at night. As an early leica user (at that time)
I had a helluva time!  Too many blades in those Summitars/Hektors/
etc.---Plenty of flare, tho.... it was the seventies and I was 
POOR and early leicas were solid and CHEAP.  Later "upgraded" 
to those "non collectible" models (canada, etc.)  Sure wish I had 
my minty IIIf RDST and IIIC and M3s etc......you know the story.
Also, being extremely poor, I had to make do with Nikon RFs, too.
Sure was glad to see those damn things go, wierd stuff, ya know...

If only I'd known

Best to U and URS<
Walt