I take your point, but it seems more complicated. On my 50mm zuiko OM lens
turning the dial does nothing when I just look through the lens, but if I
push the two release buttons (used to remove the lens from body) I can see
the blades move. This is not the case with the Sigma Pantel.
As I said, using it on my e500, having it set to 2.8 or 22 made no
difference to actual exposure...
matt
On 20/11/2007, Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx> wrote:
>
> Your lens is perfectly normal. OM lenses are normally fully open.
> Other cameras may have their lenses normally closed. When you turn the
> aperture ring on an OM lens all it does is move an internal cam that
> sets a stop point. There is no physical connection between aperture
> ring and aperture leaves. Actually closing the aperture down is the job
> of the camera body. The camera body presses on the len's activation
> lever which allows (not forces) the blades to close down to the stop
> point set by the aperture ring. The DOF preview button also acts the
> same way. Depressing it allows the blades to close down.
>
> Hold the DOF button down while you turn the aperture ring and you'll see
> the blades move with the ring.
>
> Chuck Norcutt
>
> Matthew Granger wrote:
> > *Hi All*
> >
> > * *
> >
> > *Here's a tricky question. I have an old OM lens – Sigma Pantel
> > 1:2.8f=135mmMade in Japan. On the aperture dial it has from
> > 2.8-22m then PAN 64 in red writing. *
> >
> > *I have this connected to my E500 via an adapter, however it seems the
> > aperture control is not working – seems to be set wide open. Changing
> from
> > 22 to 2.8 makes no difference to the actual exposure. *
> >
> > *Looking at the lens off the body, turning the aperture dial does not
> seem
> > to be physically attached to blades at all. It is however moving a small
> > metal arm on the inside of the mounts.*
> >
> > * *
> >
> > *Anyone know whether the lens is faulty, or what I am looking at?*
> >
> > *Matt *
> >
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> >
> >
> >
>
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--
Matt
-----------------------------------
"It is not the strongest of the species that survive, nor the most
intelligent, but the one most responsive to change."
Charles Darwin 1809 - 1882
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