[Leica] Re:two sets of aperature blades

[Summicron1 at aol.com (Summicron1@aol.com)]

since no one else is going to give you a straight answer to this, I will. I 
once asked Leitz the same question after half a day of pondering my brand new 
40 mm summicron and 90 mm elmar that came with my brand new Leica CL, back in 
dusty ancient history ca. 1975.

No, your lens does not have two sets of aperature blades. One is sufficient.

What you see from the rear is the U-shaped interior edges of the apreature 
blades coming together as they close down, it gives an illusion of there being a 
second set, but it's really just the continued inside edge of the blade from 
one side of the barrel to the other. At f-22 they come together in the middle.

There are some cameras that have a double shutter sort of arrangement, such 
as the Voigtlander Prominent, which uses a blind behind the shutter to make 
sure there is no light leaking through the Compur shutter blades. It opens just 
before the shutter clicks. But that is not the case with a Leica either.

c. trentelman

In a message dated 5/5/04 3:14:43 AM, lug-request@leica-users.org writes:


> 
> My CV 35mm pancake has two sets, but they do not
> overlap in a way that cuts the corners to make a more
> circular aperture. I don't know the why of it.
> -Marcus
> --- Karen Nakamura <mail@gpsy.com> wrote:
> >
> > OK, am I on drugs or does Leica use two sets of
> > aperture blades? It
> > seems on many of my lenses, that looking from the
> > front, there is one
> > set (main set?) that closes down, but from the rear,
> > there's another
> > set that gradually closes down and catches up at
> > f/22 or so. It's
> > very odd.
> >
> > Is this to smooth out bokeh? Or am I seeing an
> > illusion?
> >
> > Karen
>