pentacon 4/200

[rolleistef]

hiya all,
I'm currently repairing my m42 Pentacon 4/200 (wonderful lens, definitely!!), but I can't access the iris, has anybody ever dismantled that lens? i've reached the point when the lens separe into 2 parts. But what next?
thanks a lot!

 

[Fabrice2]

Hi dear "compatriote".
I got the practika B version of this wonderfull lens, it was sold with an M42 adaptor screwed on it.
When i got it the blades were not in their places,but not detached.
As far as i remember.
I couldn't get the lens in 2 parts, so i think yours is a different version (the genuine M42?).Because their is no other screws than the ones of the rear side.
I had to use a spanner wrench to access the iris blades and put them in place with my fingers.
I had to remove the rear and front elements.And be very carefull with the glass because the lenses are quite big.
The rear element is retained with 3 screws, one is longer and should go back in his original place.
Hope this could helps.

 

[rolleistef]

Hello,
Well, the blades cannot detach either. But I found that the lens could be get into two parts.
What I found out is :
The two front elements can be taken apart with a spanner, they're hold by two rings.
The back can be opened with the 3 screws you're talking about, and then, after removing the back lens element, there's another ring with a tiny little screw. Once this ring is removed, the lens naturally separe into two parts. The top one contains the iris, the other one the focusing mechanism.
The top one's got another tiny screw and is made of two parts that hold the iris. Now the problem is that those parts wouldn't separe!! I put a drop of oil on it and let the whole in the fridge but no way.
Has anybody got another solution for hard-to-take-apart things?