Did I ruin my Aus Jena 135mm f4???

[karthikrr]

Hullo,

Long time lurker, recently came into some new gear and finally an opportunity to participate in the discussions on these forums. I was preparing a list of some 18 lenses I bought in the last 30 days, to solicit views from the members on which ones to keep and which ones to sell, but it seems I must start my journey on these forums on a more scary and worrying topic.

One of the lenses I acquired in the last month is an Aus Jena 135mm f4 Sonnar (black version). It is in pretty good shape, but the glass has some light fungus on it. I am not too experienced with cleaning lenses and have been practicing on some crappy lenses (two Carenar lenses, to be precise, one 50 1.8 and the other 135 2.. Against my better judgment, having found these two lenses and a few others (Pentacon 50mm f1.8, Fujinon 55mm f2.2) easy to dismantle and work on, I rushed ahead to take apart the Aus Jena. An hour later, I am here typing a nervous first post!

I heard and saw that many of the CZJ Sonnar designs were pretty simple screw-off type lenses and generally easy to disassemble. This one did not seem to want to screw-off so easily. I then thought perhaps the ring on the front element needs to be unscrewed first to give me access to some screws. Unfortunately I do not have the proper tool for this (those rubber tube things) and my makeshift methods did not work. So I gave up on the front and decided to look at the rear.

On the back, there was a simple screw-off cover that exposed the screws around the mount. I took out four screws and found that nothing was budging. Then I noticed a big screw on the aperture ring itself and took that off. Still nothing, but while I was trying all kinds of rotations, I somehow seem to have knocked the aperture ring off its "rail" ... It now won't engage the aperture at all, and rotates freely but hits hard stops before and after largest and smallest aperture. Meanng, the aperture scale never lines up, and it hits a hard stop before f4 and one after f16, preventing me from getting the numbers to even pass under the marker.

The internet too has been very unhelpful. First of all, the 135mm f4 version is hardly talked about at all, and certainly there are no videos or guides for it. I did look at the manuals posted on this forum, but all that did was give me a headache! Does anybody have any experience at all with this lens or something similar? Have I ruined it or can I still recover from this?

If I recall, I cannot post pics in my first post? Hopefully I can in the next post. Pics follow!

Thanks,
Karthik

[karthikrr]

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[aidaho]

Nah, I don't think you've ruined anything.

That external aperture bolt should probably be screwed in only in certain position to properly engage aperture.
Where is your fungus at? General rule of the thumb: divide your lens by aperture and disassemble from the end closer to contamination.


If you already have gone from the back, you should be aware of the following: vast majority of the lenses have double action aperture control (ring+body) with some level of intricacy to it.
When going from the back it's expected for aperture control to become disengaged.

When putting the back of the lens together one must solve the riddle of correct aperture engagement first.
There are no step by step rules to aid you on how to do this, most of the time the mechanics responsible is unique.

Some lenses are very easy, some are a mindfuck (I'm looking at you, Canon FD).

[karthikrr]

Ah, that first line made me feel so much better!

So yeah, when I use a flashlight to carefully look at the screw hole on the aperture ring as it rotates, I can clearly see that the way it is supposed to work is to "slot" into a certain position and then move the internal mechanism around. However, the issue now seems to be that the ring has rotated past the point where it "slots in", and with the two hard stops, it won't rotate into the position that it needs to be in.

My suspicion is that once I open it up, the ring probably slides in vertically with a "nub" of some kind that will slot in at the right position. The screw I removed probably exists only to hold it in place. The issue is I cannot figure out how to open the damn thing up!

The fungus appears to be in a center element, definitely neither the rear nor front element. I wanted to open the front at first because there is also some dust on that end, but while videos of similar lenses seem to have the front unit just screwing out (and the whole optical block coming out as a whole), this one is ridiculously tight and I do not want to force it. I do not have the rubber pipe thing to try my hand at the front ring, but I imagine that is how I can get into the front. What I am not sure of though is whether the ring rotates out, or a bigger unit rotates out. More critically, HOW DOES ONE know if the ring is STUCK with glue, or meant to rotate out? I don't want to spend hours trying to rotate it and then using heat and acetone and what not only to find its glued in!

As for the rear, I didn't want to go in that way because I was scared of messing up the aperture mechanism! But when I did try, after removing all the screws I found in the back, it does not move a millimeter in any direction! I have no clue whats going on at that end ... Typically, once all the rear screws come off, the mount and more just lifts out, right? In this case, NOTHING moves. I'm stumped!

[karthikrr]

AND the ring is out ... Fashioned a removal device out of a bottle of powder and double-sided tape. Worked perfectly, now the front ring is out and I can see how to remove either the front element or the whole optical block (at least the part of it that is in front of the aperture blades anyway) ... Will keep working on it and document the process. Phew, I can breathe better now.