Meyer Optik Orestor 100: Aperture "button"?

Nikos · Expire: 2015-01-02

I bought an Orestor 100mm f2.8 for just �55.
Now I am trying to see if it is defective.

I noticed that the aperture blades are stuck.
Ater cursing the seller I noticed something like a button.

Pressing it, makes the aperture blades move.
As you set the aperture to its maximum value, it gets depressed again.
At maxixum aperture, there is resistance and it cannot be pressed at all.
I suppose this is a depth preview button.

It seems I am missing something here.
This would be a very cumbersome way to close the aperture.
There is also a thin lever near the exit pupil. I would expect that pressing it would make the aperture open.
However nothing happens.

Any ideas?

dimitrygo · Joined: 01 Apr 2009 Posts: 561

Yes this is a DOF preview button and normally when you press it it closes the apreture and when you release it it returns back by itself. But yours is a bit faulty in this regard, it doesn't return by itself (mine lens bahaves the same Smile

). When everything works as it should you need either to use flanged adapter or somehow fix the aperture activating pin in order to be able to use the lens at different apertures. But since your lens has this nice flaw you actually can use this switch as some sort of A/M switch. You just need to remember that every time you change the aperture you need first to fully open it.

exaklaus · Expire: 2011-12-02

Yes, it seems that your lens needs a service! Diaphragm should close by pressing that button or the rearside pin. And should reopen by releasing button or pin, again.
Klaus