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GanjaTron
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 15, 2005 - 05:25 pm: | 
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Hi all,
I've got a Zeiss Distagon 2.8/25mm with bayonet mount for the Rollei SL35 et al. GREAT lens. Unfortunately its aperture seems to have gummed up and is sluggish when I press the plunger on the lens mount.
As far as I can tell after removing the bayonet ring, the plunger spring which actuates the aperture lever is weak and needs adjusting, only there's no easy way to get at it. The aperture blades themselves are clean and show no signs of gumming.
I assume this is a common problem with these lens, so I'm sure somebody's gone about fixing this. I'm a bit apprehensive about dismantling it, however, and there's no apparent way to do so after removing the bayonet ring. All I see are two lacquered screws for the infinity setting, and I don't feel like messing with those. Any way to open this baby up without misadjusting the focus?
Any help appreciated!
--Roland |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 16, 2005 - 10:00 am: |
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Before assuming the spring is weak, I would check further into cleanliness: there are other things that can get gummed up besides the blades, particularly the actuating ring that drives the blades.
I haven't worked on this particular lens, so I can't help with specifics. Access might be from the front, though, rather than the rear... |
GanjaTron
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 17, 2005 - 05:24 am: |
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There are no visible signs of gumming, tho as you point out the actuating ring could be a culprit. To check it I'd have to completely dismantle the aperture down to the blades.
There's no apparent way to open up the front (no notched ring). I guess you remove the infinity screws and the whole helical comes out. God knows if I'll get it back together, tho... |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 17, 2005 - 02:23 pm: |
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You should be very careful when rebending springs in auto aperture mechanisms. Sometimes they are matched to other parts of this mechanism (including the actuating mechanism inside the camera), and it may happen that the whole mechanism does not work correctly after changing the power of a spring.
Even if there are no visible signs of oil or grease on the aperture blades they actually may be gummed up. This is a common fault of auto aperture lenses and can be cured by cleaning the blades. |
GanjaTron
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 17, 2005 - 02:52 pm: |
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Ok, I give in... I'll rip it apart. :^)
But pray tell, how??? Obviously Zeiss wanted to discourage anyone from fiddling with their stuff, so there are no set screws or rings to remove from the outside. Maybe it's something tricky requiring a friction tool, but I'm not gonna force this baby. I'll look at this more closely tomorrow & let you know. Meanwhile, thanks for the replies.
--Roland |
GanjaTron
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 19, 2005 - 02:49 pm: |
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Well, I've removed the infinity screws and *&[email protected] the focus, but the damn helical won't simply screw out because it's still coupled to the aperture ring on the outside. I would imagine the lens has a rear section which is screwed on seamlessly, requiring a special friction tool to take it apart. Attempting this without the right tools will definitely destroy the lens.
I guess I'll have to swallow my pride and leave this to a pro, only he'll most likely charge more than the frigging lens is worth... |
aidan piers
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 18, 2005 - 07:11 pm: |
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Hi GanjaTron,
Somewhere I have exploded factoy drawings of 1970's Zeiss lenses for Rollei SLR's. I know for sure that I have drawings for the Planar 1,4/50 and the 1,8/50. It will take a week or two to dig them out and see what I really do have, but if you are interested, let me know and I could perhaps mail something to you. |
GanjaTron
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 22, 2005 - 02:57 pm: |
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Hi aidan,
thanks, but I've now taken the lens to a pro along with my Distagon 1.4/35mm. I've seen the exploded diags of the Planar 1.8/50 in Prochnow's Rollei Technical Report, and they didn't help much. According to the repair guy, the Distagons differ considerably in their construction from the Planars. Particularly the 1.4/35mm is radically different from any of the other Zeiss lenses (triangular aperture!) and extra nasty to dismantle and service.
Regards,
--Roland |
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