| Author |
Message |
    
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 22, 2006 - 06:21 pm: | 
|
Can anyone help get me into this Biotar? It really has me baffled. Nameplate unscrews, front cell unscrews, rear cell moves but just turns and turns (unless its the longest thread I have ever seen)
There are no screws anywhere that I can see to get into the aperture and helical.
Is is one of the same vintage as the Contax D its attached to. Bright aluminum barrel, preset aperture. |
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 22, 2006 - 06:48 pm: |
|
OK - rear is good. There is a retaining ring for the rear cell that is difficult to get at, but I spun it out with the aid of a slotted screwdriver (good thing it was not too tight!)
Then rear cell simply pops out with a few hard raps.
Middle cell unscrews with spanner slots.
Now, I see a thin (tight) retaining ring at the back of the lens, but its not possible to get at with my spanners. Is this the one that has to come out to get the focus helical apart? |
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 22, 2006 - 07:07 pm: |
|
Talk about your self help forum ;) And that retaining ring is out!
Lens is apart - should just be the large screw to remove the stop on the helical so I can separate, clean and relubricate.
I'll have to go deeper still - I want those bright alloy exterior pieces off so I can clean and shine them up.
Time for a break on this one. Any more tips are greatly appreciated! |
Henry
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 22, 2006 - 07:30 pm: |
|
I can't wait for the next installment.
This is a real cliffhanger...
:-) |
Michael Linn
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 22, 2006 - 08:55 pm: |
|
Biotars are meant to build character in those who attempt to repair them- or use them.
If you did not spend enough time noting and commenting mentally on the repetition of the lens serial number on the interior components of the lens you are possibly attempting to move too quickly.
Carl Zeiss, if he were still around today, would possibly say that his lens was a classic design, and that it required a bit of patience to service, not that you are lacking patience!
Just that it's later Japanese copies (ALL Japanese 50-58mm lenses of the era were copies) were easier to service.
Carl's earlier lenses (read Sonnar) in this 35mm group are not so challenging to service although not by much.
I have serviced and used this lens in several mounts and will be happy to help if possible. I have a cut away photo of it in M42 mount if that would help.
Any time you spend restoring this lens will be repaid by the photographs you might get.
http://contaximages.com/user.php?id=466&page=user_images |
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 23, 2006 - 03:30 pm: |
|
Sure, I'll take the cut away photo.
Sorry, I really did sit there puzzled for a couple of hours, posted, then all the pieces really clicked. |
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 25, 2006 - 06:21 pm: |
|
The cliffhanger ends - its done. Summary:
1. Remove the outer spanner ring you see in the back of the lens.
2. Rear cell will fall out with a tap
3. Unscrew middle cell with spanners
4. Unscrew nameplate with friction tool
5. Unscrew front cell
6. Unscrew remaining spanner ring in back of lens
7. Separate focusing mount from optical mount
8. Remove infinity stop screw - you can unscrew the double helical - BE CAREFUL TO MARK WHERE THINGS COME APART OR IT COULD BE A REAL PUZZLE LATER! You can service the helical.
9. Remove spanner ring behind diaphragm - you can separate the aperture from the preselect mechanism (watch for the 4 springs)
10. Unscrew the aperture selector
11. I clean all the corroded aluminum with aluminum wheel polish (comes off black, buff it clean)
12. Everything backwards and with luck, collimation will be on infinity.
All in all, a success here! Hope this helps someone in the future.
Cheers
Mike |
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 25, 2006 - 06:22 pm: |
|
in step 10, you need to remove the screw engaging the aperture selector ring to the diaphragm. |
Henry
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 26, 2006 - 08:56 am: |
|
Excellent!
Mike, how would you like to put this as an article in our lens section? Take any photos as you were hanging by your fingernails off the cliff?
Henry |
Chekawa
Tinkerer
Username: Chekawa
Post Number: 7
Registered: 10-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 23, 2006 - 11:41 pm: |
|
Going to do the same here on one I just received. This post is a little old so I guess the photos were not done. I will keep a running photo record of doing mine for anyone in the future. If anyone knows of anything related to this on CZ unit it would help.Feel free to email me. Thanks. |
Steve_s
Tinkerer
Username: Steve_s
Post Number: 20
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 24, 2006 - 01:19 pm: |
|
I managed to get mine apart a few months back thanks to this thread. Thanks Mike - and thanks Michael Linn for the image! I would never have believed a manufacturer could have made a lens so confoundedly difficult to dismantle.
One thing I would recommend, Chekawa, if yours is as tightly assembled as mine was, is that you separate the focusing mount (steps 6. and 7.) before you do steps 4. and 5. The sliders for the helical form part of the focus-mount and therefore are aluminium and relatively easy to damage if you have to apply a lot of torque.
If you are wondering which is the spanner ring referred to in step 6., it is the one you can't see, right out by the helical and probably covered in grease! Hope you have a tool to reach it. I didn't and had to make one.
Best of luck! |
Chekawa
Tinkerer
Username: Chekawa
Post Number: 11
Registered: 10-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 25, 2006 - 01:20 am: |
|
Wow, Steve_s thanks for posting back. That is very good information on the focus-mount. Your additional comments will be most helpful.
Thanks Again and another lens is saved by another post.
Be well and worry free! |
