Zuiko 42mm f1.2 aperture issue

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nickthetasmaniac

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Hi all,

I'm considering purchasing a Pen FT with Zuiko 42/f1.2, but the lens appears to have an aperture issue.

As the seller describes it, the aperture is always stopped-down to the set aperture. Ie. no open-aperture framing and focussing. To me this sounds like an issue with the aperture mechanism, rather than regular oily/sticky blades.

Any idea what might be going on? The price reflects the issues, I'd just like to know how much of a headache it could be...

I can request more info, but I'm not able to inspect the gear in person (different state).

Thanks!
 
Hi Nick, it may not be a serious issue, maybe a matter of gummy lube. With the lens mounted, see a squarish button on the lens's mount nearest the camera's shutter release delay lever. That is the manual stop-down button. Yours may be stuck in the depressed position. I just checked one of my lenses (70mm f/2) and found it somewhat sticky probably due to ancient lube.
That is an unusual/rare lens. Good luck!
 
Could be a broken or unhooked spring. If the glass is clean and the price is good, I wouldn't let this get in the way.

Has the seller sent video of the camera's operation?
 
If the price is right and the glass in good condition I would go for it, the Pen lenses are fairly easy to dismantle and deal with simple issues or clean the glass elements, if you have some experience. If the spring that holds the aperture blades open is worn, broken or dislodged this could be fiddly to fix or replace. Oily blades could also prevent the spring from doing its job. Doug is probably onto it, though if the seller fixes the issue the price might go up!

I was lucky to find a 42mm 1.2 in a local camera shop a few weeks ago for a very good price, the front element has a lot of marks which makes it less contrasty, but overall it's an impressive-looking lens. I will put some film through my Pen FT soon and try it out properly.
 
The issue may also be a problem with the camera shutter rather than the lens. I have an old Pen that has a shutter that always sticks open. When a lens is mounted and the shutter released, the mirror is locked open and the lens aperture stopped down, and it stays there. So when I adjust the lens aperture, it exhibits the same behaviour that you have described. So you ought to find out whether the 42mm lens is attached to the camera or not, and if so, is it possible to see through the viewfinder (i.e. is the shutter working properly).
 
Thanks for the responses everyone, very helpful.

@Doug - my guess/hope was that it had something to do with the dof button sticking.

@Largedrink - According to the seller the body (including shutter) operates properly, and they have shared plenty of negs. The only issue being a very dim viewfinder at smaller apertures (due to the stop-down problem).

I'm very tempted to buy it and see what can be done. As mentioned, it's a very interesting (and usually very expensive) lens...
 
Let us know if you decide to buy it. If it's useful, I just now disassembled my own 42mm 1.2 from the back and cleaned the rear elements, and took notes/photos as I was doing it. The disassembly was easy but the reassembly quite fiddly!
 
Hi Nick,
I don't know much about the Pen series but if the lens is in good shape and there's a prospect of sorting that, perhaps it is worth taking a punt on the combination even if the body is an unknown quantity? Because even if it was a total loss, you'd still end up with a lens which, as Doug says, is rare and desirable. Besides which maybe the body could be a goer anyway? Personally, I would take a punt, but perhaps I am also a bad influence.
Cheers
Brett
 
Might be a body issue rather than the lens. The body mechanism is what stops the lens down. But if the price is right go for it. Any of these old cameras probably need a CLA even if a superficial inspections shows it to be working.
 
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