Meyer-Optik. Orestegor 200 / aperture problem.

Lloydy · Expire: 2022-01-01

I picked a nice M-O Gorlitz Orestegor , spotless glass and a very nice body. But I don't think the aperture closes down to its smallest position.
I know how the pre set stop down aperture works, lifting the spring loaded ring to set the required aperture etc. But the f stop indicator numbers seem out of sync' with the actual aperture.
The aperture blades will open fully, I can see that they fully retract - this must be the f4 position, but the ring indicates just below f5.6.
Go the other way to fully closed the ring indicates f22, which is as far as the ring should go, but the aperture blades seem to be a bit wide for f22 - if you look at the picture below the blades are as closed as they will go and the ring says f22. Does that look like f22? If someone else has one of these lenses I would like to see a picture of the correct f22 on the blades.

I think the spring loaded stop down pre set ring has slipped, but I can't see how to remove it to adjust it. Any thoughts on adjusting it would be great.

Gonzoo · Joined: 29 Mar 2010 Posts: 231

AFAIK you can limit the aperture ring movement to a certain range (e.g. wide open to f8 ). I think your lens is limited to an aperture between 16 and 22. You can (un)do that limitation by lifting the aperture ring towards the front ring and turning it.

Lloydy · Expire: 2022-01-01

Gonzoo · Joined: 29 Mar 2010 Posts: 231

F22 has a smaller opening definitely. The apterture ring is disassembled from the front in a few steps, should be easy to repair.

Excalibur · Expire: 2014-04-21

Lloydy · Expire: 2022-01-01

I was so pleased with this lens, I've had it a while but not used it because it is Exacta mount, then I got the Pentacon 135 in M42 and the factory adapter is interchangeable between the two lenses. I only noticed this last night, so I took the Orestegor out today and tried it, and I loved it. But tonight disaster struck, when I took the lens off, and turned the aperture ring to admire the lovely circle of the blades - one came off! Crying or Very sad

so now I have got to dismantle the lens and repair the aperture mechanism completely. I could live with the aperture not closing fully which was the known fault. At least it opened fully, or maybe even opened a bit too far?

Anyway, it's got to be fixed. So how does it come apart? I've had the front name ring off and all I can see is another optical clamp ring. So I'm guessing the optics have to be removed from the front to get at the mechanicals? All help and advice is gratefully recieved, I really want this lens working again.

edit....
I've just looked at the pictures I took this afternoon, late in the rain. This was wide open, straight out of the camera. I am oficially pissed off now!

Lloydy · Expire: 2022-01-01

It didn't cost me very much, so I went in and had a go at it. The front glass all came out easy enough, but I can't for the life of me get the body apart to get at the stupid aperture ring!
But while I was in there I figured out that one blade had jumped out, and there was no way it was going back in the empty slot, where the pin rides and is just visible in the picture. A closer inspection determined that 6 blades had jumped one slot and had to be moved back in to place then the stray blade could be returned to its right place. It was a fiddle, but the dental style picks proved invaluable and they were all carefully prised back into position. And it works, except for the original problem. I think the blades jumping was oil on the blades, so they've been cleaned with nail polish remover.

And I got the glass back in in the right order, that's good enough for infinity!

Gonzoo · Joined: 29 Mar 2010 Posts: 231

zoran.rilak · Joined: 12 Jun 2018 Posts: 1

Almost five years later but hey, maybe somebody will find this useful.

Lloydy, your issue is that all of your aperture blades have slipped forward by one notch. That is why you're not getting the smallest aperture at f/22 (blades don't close enough from being too forward) and also why you are seeing max aperture at around f/5.6 (blades retract too soon, again from being too forward). To fix, just push one blade out by unhooking its pin, then unhook and slide all the blades back by one slot in counterclockwise direction.

In my experience, Orestegors' apertures are flimsy affairs that will fall out especially easily at f/8 if the lens is shaken or hit. I've fixed two with the exact same problem as you describe.