ICAREX concave Zeiss ULTRON 1.8/50mm disassemble

[Pancolart]

I have nice specimen sadly aperture pin was missing. I decided to repair it since i have few Icarex bayonet lenses that could serve as donors. I soon found out i won't be able to put lens auto function back since it's really complicated. I have lens mechanics fully in parts now.

Anyway did someone successfully cleaned glass compartment? I still have it in one piece and i don't know where to start - from rear or front end. Most of dust is above the aperture blades.

I don't intend to make photos of procedure but if any interest i will.

[Pancolart]

There you can see Auto function complicated part that i will be leaving out.
And lovely unopened glass compartment.

[spleenone]

Legendary Zeiss Ultron. Apparently in good condition. Then you should hang out some pics if you have success in cleaning. I would really happy to see some. Thanks.

[Pancolart]

Anyone cleaned it successfully please let me know. I really don't want to drill holes in front label if unnecessary. I am pretty sure i won't get to the dusty element from behind.

[Pancolart]

DONE! Lens together again with working aperture and correct infinity.

For few days a was just watching disassembled parts on my table and feeling tension. Thinking what a shame to ruin rare and expensive lens.

Last two days i was progressing bit by bit. The toughest part: adjusting infinity. After several attempts fully unscrewing and starting at different positions by sheer luck it came to me that 5 screws (beneath those big 3 visible from outside) play a role in adjusting. Their order is important! You can also gain 4mm back and forth with those big outside 3 screws. So all back screws in fact matters.

As i said i skipped repairing auto mechanism (a part had to be taken out) so now preset lens. Funny trivia: Icarex lenses do not have click-step aperture select. Aperture ring just slides. Checked on Dynarex and Scoparex too.

I decided not to clean glass inside. Lens has some tiny dust particles but to make drill holes in front label (though small) it felt unjustifiable. I wouldn't hesitate on 20 EUR worth lens but here...

[AhamB]

[Sevo]

If rubber stops don't get enough grip on a lens bezel, removable double sided adhesive tape (as used for temporarily attaching stuff to cars) can help, too.

[Pancolart]

Thank you both for advice. Label ring is very narrow. Thin inner silver ring sticks out thus preventing good grip of rubber.

[Ramon]

I appreciate this is an old thread but the info may be useful to someone.

To remove the front ring, remove the 2 grubscrews on the outside of the chrome ring, the front black ring with writing on it will then just drop out from the front. If it doesn't drop out then you may need to push from behind but you can only do that if you have unscrewed the focus helicoid.

The front lens housing is screwed into the main block, look for the 2 little protruding ears poking out, by using these ears you can unscrew the housing in the normal anti-clockwise direction. This will seperate the front lens group from the rear group and aperture block.

[paleblue]

For any new visitors to this thread, which is apparently one of the primary resources for disassembling an Ultron(!), I want to add from my own limited experience with this lens - the thin silver inner ring is part of the label ring. It screws off in a single piece.

I'm trying to reach some stuck aperture blades myself, and pretty intimidated by the imminent infinity focus Pancolart described! Fingers crossed....

[jamaeolus]

Another useful tip for challenging name bezels. Use "BluTak" its the sticky putty stuff marketed to mount posters and the like. push iinto the name letters and all the way around under your rubber ring. Gives much better grip than the rubber alone. Cleans off nicely. Also useful for quick and dirty adaptation to test lenses that you don't have proper adapter for:

http://forum.mflenses.com/blutack-adapter-for-ica-litonar-to-a7ii-t75541.html

[huypn12]

Dear all,

I have a Tessar in Icarex BM mount and unfortunately it currently have displaced aperture blades. Certainly, I need to open the lens to access to the aperture block to replace these blades, but sadly I do not know where to start.
I have observed that the lens has 3 big screw at the front end, and one other smaller screw hides beneath, toward the inner side of the mounting ring. However, I am hesitating which one needs to be unscrewed first. Moreover, I need to know what should I pay attention while disassembling. Please give me some clues on this rare kind of lens.

Thanks for all your helps,