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Carl Zeiss Jena 135/3.5 Repair
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PostPosted: Fri Apr 01, 2011 7:56 pm    Post subject: Carl Zeiss Jena 135/3.5 Repair Reply with quote

Hello,

Has anyone here repaired this lens following the instructions found here?

http://www.andrew.brown.dsl.pipex.com/articles/czj135svc/

Can anyone tell me how many turns it took to set the infinity focus adjustment with your lens? It wasn't because I forgot to count the turns during disassembly (I could not). My lens had another problem other than the stuck diaphragm assembly, the focus ring would turn stiffly but the lens would not focus. Turning the focus ring from MFD to infinity, the glass elements would remain immobile.

Following the disassembly instructions up to figure 4 and 5, and peering into the lens, I could see that the helicoid screws were seized and turning the focus ring would spin the aperture blade assembly holder (item 10 in Figure 12) along with the front and middle elements. I removed the front bezel, took off the helicoid retaining ring (which was loose) so that I can exert some pressure against the front element to overcome the inertia of the seized helicoids and spin the focusing ring off.

I have cleaned all of the components and am ready to reassemble the lens together but I do not have the number of turns required to set the infinity focus. I thought I would ask here in the forum because the setting for infinity focus should pretty well be the same for all of these lenses of similar vintage. The serial number is 104432.

Your help would be most appreciated.

Thanks,


PostPosted: Fri Apr 01, 2011 8:23 pm    Post subject: Reply with quote

Screw the base back on until it will go no further - don't overtighten. The red line will go past infinity by 1/4 to 1/3 of a turn and end up somewhere near 2m (guess from memory!). Now turn the base in the opposite direction until the red line is a little to the left of infinity (see Fig. 4). Now replace the end stop screw. Check that the base now moves easily between the two stops - infinity and close focus

When I first started cleaning copies of this lens I used the counting method. However I quickly found that the base moves on the last full turn. To check on later lenses, after removing the end stop screw, I turned the base past infinity to see how far it would go. It never went more than 1/4 - 1/3 turn as indicated above (remember this is from memory - if it goes 1/2 a turn don't worry). I've serviced maybe 8-10 copies of the lens. All were the same - but yours may be different!


PostPosted: Fri Apr 01, 2011 9:06 pm    Post subject: Reply with quote

Thanks for your reply, I'll give it a try tonight.


PostPosted: Fri Apr 01, 2011 9:15 pm    Post subject: Reply with quote

http://www.andrew.brown.dsl.pipex.com/articles/czj135svc/

this manual is complicated a bit ?


PostPosted: Wed Aug 17, 2011 10:17 am    Post subject: Reply with quote

I need help to get the infinity focusing right...

I didn't manage to count the revolutions when I removed the focusing guide ring because the focusing barrel fell off downwards, and now I can't manage to get the infinity focus right.

Following the advice given by sichko in the thread above, my focusing guide ring almost turns a full revolution after the infinity mark (to about the 4m indicator) when turning it as much as possible.

Now I have managed to put the lens together, but it can't focus properly; I can only focus between just under 1m to 3m indicators. And if I turn the focusing guide ring so it correctly indicate infinity, the rods (shown in figure 3 by the red arrows of the manual linked to above) will evently jump out of their tracks if I try to focus at the shorter end of the scale.

Did anyone happen to make a more exact calculation of how everything should be put back together?

Thanks in advance


PostPosted: Wed Aug 17, 2011 11:38 am    Post subject: Reply with quote

Mewe, can you check for "V" shaped marks on the barrel and helicoid? They indicate the correct screw-in position of the helicoid. Nearly all of my Pentacon or Zeiss Jena glasses feature these marks.

If the rods jump out of their guidance, most likely you haven't used the correct screw-in position.


PostPosted: Wed Aug 17, 2011 12:58 pm    Post subject: Reply with quote

Thanks for the tip. But I'm struggling to find any indicators at all. Where exactly is this "V" shaped marks supposed to be? On the inside of the barrel, on the lens body above the helicoid?