tele-westanar 135 2.8 aperture mechanism

judaskgb · Joined: 29 May 2011 Posts: 4

hi.i am new to servicing lenses .

i was servicing a tele-westanar that had issues on focusing ( at the middle of run it was difficult to turn) .
after having :
unscrewed front lens element and the focusing ring , the aperture blades has shut completely stopped down .
the problem is that i can't find a way to reach the aperture mechanism , i do not see any screw or any part of the lens that can be unscrewed , i can see the blades through the inside of the lens ( havng unscrewed the front lens glass )
( btw the aperture mechanism wasn't working very well either , it had some issues , as if the aperture ring isn't perfectly connected to the blades lever ).
i tried reassembling the lens but the blades remain shut
does anyone have a service manual of this lens or could tell me how to get to the aperture mechanism ?

Gonzoo · Joined: 29 Mar 2010 Posts: 231

Hi judaskgb, posting some pictures of your disassembly process would be helpful.

If the aperture mechanism does not work well, there are several possible reasons: oil/lubricant on blades, weak spring, connection lost to aperture ring etc.

judaskgb · Joined: 29 May 2011 Posts: 4

here is the lens

the lens from above , having unscrewed the lens element and the focusing ring.

here is where i am stuck , i domnot know how to get to the aperture mechanism , i can't see any screw .

Maybe i have to unscrew the back lens/irsi assembly from inside the focusing mechanism?

more images of the disassembled lens

photos taken with my just repaired pentacon electric 29 2.8 ( unscrewed focusing ring)

Gonzoo · Joined: 29 Mar 2010 Posts: 231

Did you try to disassemble the rear part of the lens? In the last picture you can see the retaining ring of the rear element, maybe you can reach the aperture when unscrewing the outer ring with a lens wrench.

judaskgb · Joined: 29 May 2011 Posts: 4

actually i do not have any lens wrench . i wasn't planning on doing any repair on my lenses it just happened that i tried to open this one.
i'll order one on ebay .
which should i get ? i plan on servicing or trying to repair old lenses so i would like to have a good piece of equipment .

are these ones good?

Click here to see on Ebay
Click here to see on Ebay

Gonzoo · Joined: 29 Mar 2010 Posts: 231

There are several models available. Afaik you can find some discussion on tools in this forum. Don't know the thread though. Try searching for "wrench" or "tool(s)"

judaskgb · Joined: 29 May 2011 Posts: 4

done.
with the wench i managed a complete disassemble , cleaning of optical groups and reassemble of the lens.
i'll post the images in the next days.
after greasing all the mechanical parts and a cleaning with isopropilic alcool of the optical groups , removal of dust between lense etc.. now my westenar is waterclear and smooth ( only prob remianing a certain stiffness in the middle part of focusing , i think because the optic has taken a bump or more during its life so it is not so round anymore )