The Pentax Takumar M42 lenses that I have also have the A and M selection.
I use them with a simple adapter on my E-1. But, if you accidentally push
the slide to A, as I did a few days ago, all of the shots are at full
aperture.
Jim Nichols
Tullahoma, TN USA
----- Original Message -----
From: "Moose" <olymoose@xxxxxxxxx>
To: "Olympus Camera Discussion" <olympus@xxxxxxxxxxxxxxxxx>
Sent: Wednesday, January 23, 2013 2:14 PM
Subject: Re: [OM] m42 zuiko on Can*n
> On 1/23/2013 7:13 AM, Frank Wijsmuller wrote:
>> Just bought one of these Zuiko's: <http://www.pbase.com/image/95819343>
>>
>> ... I would like to keep the pin *and* focus for infinity.
>
> I think you may misunderstand how the lenses work. "The M42-EOS adapter
> had to be turned down so that it cleared the
> aperture info pin on the lens. "
>
> I know nothing specific about the Oly FTL or its lenses. What follows is
> generic info about M42 lenses with auto
> aperture capability.
>
> That is not an 'info' pin, but an aperture operation pin. These cameras
> had no idea of the actual aperture setting.
> Unless the pin is pressed in, the aperture stays all the way open. The
> camera presses it in for TTL metering, if
> available in the body, and to close the aperture for exposure.
>
> Because this aperture pin operation was a sort of ad hoc adaptation, thing
> aren't always consistent.
>
> For example, there are two kinds of M42 adapters. One ignores the pin. The
> other has a flange at the back that presses
> the pin in as the lens is screwed into the adapter. It sounds like you may
> have cut away the flange on your adapter that
> does that.
>
> I have both kinds, as I have an old Tessar, with pre-set aperture
> operation, that protrudes too far back to fit in an
> adapter with the flange. The other nicely operates the pin on a more
> modern lens.
>
> If I fit a later lens with pin in the old style adapter, the aperture ring
> doesn't adjust the diaphragm, and it's always
> wide open on the Canon body.
>
> UNLESS, it's a lens designed for all bodies. I have an "Auto Image" brand
> 28/2.8 that has a ring behind the aperture
> ring with 'A' and 'M' settings. At the M setting, it pulls the pin in for
> manual aperture operation on cameras without
> auto aperture capability.
>
> Sooo ... Unless the Oly lenses have a Manual setting, you probably need a
> new adapter.
>
> Push My Pin Moose
>
> --
> What if the Hokey Pokey *IS* what it's all about?
> --
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