Carl Zeiss Jena 50mm f2.8 Lens Disassembly and Diaphragm Cleaning
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- Опубликовано: 8 июл 2024
- Full disassembly and diagram cleaning of a Carl Zeiss Jena 50mm f2.8 lens. This is the M42 earlier zebra style version of the lens.
Disassembly is moderately complex, and much more complex than comparable 50mm lens. The major annoyance is that the aperture blades tend to fall out once you remove the front glass piece. Be sure to hold on the diaphragm front layer if you are cleaning the diaphragm.
The rather intricate mechanical design also gave me some problems and I needed to add a bit of lubricant to keep things moving well.
Full time of video was around 50 minutes.
photography.mattbierner.com 
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Excellent and I would like to thank you as I have just purchased one.
for those who mayby struggled a bit over this overall great tutorial, I noticed one mistake that took me a while to see..Closely before the situation Matt separates (and later combines again) the helicoid and the outer focussing barrel, he says this is at the position of INFINITY. This is not the case, it is at the OPPOSITE side of the scale, the NEAR area (1,2 ft) . Otherwise you physically would not be able to screw the helicoid at all, because it would just fall out. Just try it out, any lens is on it's most screwed OUTWARD position in the NEAR area, at infinity lenses are at the most screwed IN position..hope this helps.
Soooo much easier to follow the process when explained accurately. Thank goodness it wasn't another 'silent movie'. Many thanks Matt.
Thanx, Fixed mine. Someone assembly in wrong way, grease was old. Now work like a new but look old :)
The diaphragm will always fall out in my copy once put back in the focusing mechanism when I try to focus. Any thoughts?
I opened the back and cleaned the aperture lever/mechanism and it works great now. When trying to close it I found a tiny sphere sitting there but I have no idea where it came from. Everything works fine so I'm a bit confused.. thanks for the great video btw!
Sounds like the ball bearing which makes the aperture ring click.
@@jamespassas9441 it indeed is, I'm trying hard to get it back in place lmao 🤣
@@edouhoekie Just put a little grease on it to hold it in place while you assemble the lens.
@@victor9501 I managed, the spring was a bit over stretched so I replaced it and greased it up.
I bought one on eBay. Within days of receipt the focus ring started to get progressively stiffer, until it siezed completely. I have just spent the entire day dissassembling and reassembling the lens, several times. I got the focus’s threads squeaky clean ad regreased with pig iron30 grease, but the focus rings still won’t budge. Grrrrr!
Thank you 🤗🤗🤗🤗🤗
Anyway that you have disassembled the CZJ 135mm f4 EXA mount zebra edition? I’m struggling to find a tutorial or repair guide to fix the Stuck aperture blades
Do you repair these CZJ lenses ? I have a flektagon that needs aperture blades cleaned and other repairs. If not can you recommend someone who does this repair ?
What if there are no screws on the back plate? (On this lens)...how do I get in?
Hello, I have this lens, but my diaphragm is not working. Do you have a tutorial on disassembling this lens? (Carl Zeiss Jena MC 180mm Sonnar)
thanks for your help
Thanks Matt. Your video superb. I took lens apart yesterday and though there were subtle differences I was able to clean all the bits, reassemble the blades, and re-grease the focus. Your video gave me the confidence to proceed, and now I'm in possession of a great piece of kit! Mind you, I was knackered at the end of it lol .... ;)
Thank you! I cleaned the blades on my Tessar and it's snappy and new again!
This lens is weird. Even after cleaning and degreasing all helicoids and applying new much softer grease, the focus ring turns so hard.
Just changed the helicoid grease here. My notes: front element out is the closest distance, you need to attach-detach from there, not infinity. For attaching go 1 cm further than the place where the focus guide metal and screw align each other. There are different versions of this 'zebra lens' too, my version does not have the three screws after the front element. there was nothing indeed to detach it which I puzzled but I did not need to detach it so I left the blades as they were without cleaning. When you detach the aperture selector ring, there is a metal bearing ball that clicks the apertures in place and springs out as you remove the ring. Be careful with that, do not lose it, and re-attaching is quite a headache, grease it before with a sticky grease and reattach the ring first and ball with a tweezer on the last f22 dent checking if it fits in its place.
You dont know how much i appreciate your comment. It saved me after a lot of time wasted trying to attach the element.
28:46 this part locked focus ring 28:46 ☹️
Hi Matt, great video.
I have the 1.8 version of this lens and I'm wondering if it is the same construction? I need to get inside and clean and re-grease the focusing ring as it is very stiff. I see in this video at about 9 mins 30 secs where you separate the two sections, can I go this far and then clean and re-grease at this point, any tips from yourself or anyone with experience are much appreciated.
Bro youre a wizard. respect.
Thank you Matt for your work and for sharing it with others. I bought one of this lenses and the focus ring was rotating without moving any elements inside. Your video helped me disassemble the lens and fix it. Good luck!
How difficult is it to repair one that is seized and won't focus?
Great job and explanation, step by step. Thumbs up!!
I have the same lens!
An excellent tutorial, very informative and useful.
you de-clicked the aperture control ring then? No mention of the ball bearing and small spring that sits inside the aperture control ring.
Thank you so much for this amazingly detailed tutorial! :)
Thank you very much. Helps me clean my Bereoflex 35mm
Many thanks- your video allowed me to repair my copy of this lens, cheers!
Thank you very much for this excellent explanation.
I miss seeing your tutorials on lens repair and cleaning.
Thank you so much for this Matt,...I got one of these lenses recently complete with fungus. Now I can safely go about cleaning it properly :)
How on earth do you get the two threads back together? Ive been trying for an hour to get the aperture assembly back into the focus track. Any tips?
Good video . Question : how do you know how big or small the smallest diaphragma aperture must be when setting the screws on the side-bar that commands it ? Shouldn't you first set the diaphragma completely open , and towards that setting tighten the screws , instead of the other way around like you do , by "estimating" the smallness of the f=22 smallest opening and by that thightening your side-bar screws ? If you estimate the smallest aperture , then how do you know if its f value corresponds to the marked one on the f-setting ring ?
If you really wanted, you could measure the diameter of the opening and match it to the f-stop value (eg. f/4 = 50mm/4 = 12.5mm opening size). But I usually just eyeball it and compare it to other lenses.
Thank you for the video. I'm stuck at the point where I have merged the two pieces together, but when I turn the focus ring, it comes off track? Can you help me out with this?
Great tutorial - helped me rescue a dubious eBay purchase and create a fully working lens!
To remove the focus ring, there is a locking ring with spanning wrench notches holding it in place. Undo that ring and you will find another helicoid but very fine threads. This helicoid is often the cause of tight focus. The locking ring can be hard to undo as sometimes it has a spot of varnish that keeps it from loosening. Reassemble the lens with the focus unit fully back and then tighten the locking ring at infinity. You will now need to align the focus to the focus ring.
You would be surprised, but I have cleaned and re-greased both helicoids inside the lens, and it worked super smooth until I put that "track" inside that holds one of those helicoids inside in the exact position so it only moves up and down. So in certain cases, that tracking part causes all the problems with hard focusing, even when you clean all helicoids and put new grease everywhere. No success in my case.
Thanks very detailed. I have a 135mmf3.5 zebra version, the front ring that secures the front element wont come off. Do you have a video for front glass elements?
I spend 2 hours to disassembly/assembly my Jena for complete cleaning, each lense are crystal clear now, thank's.
At the 1st testing the focus ring don't go until infinite, it's was a mistake, at the 2nd try it goes to the infinite symbol but the focus is ok until 4-5 meters, no more. any idea?
Thanks for sharing, will you ever make a tutorial for the Biotar?
hey Matt, thanks for the great video, it helped me alot deassembling my tessar. my copy has a loose focusring. i can move it, but it wont effect the focalrange of the lense. i have no idea how to fix this. any idea what i can do? thank you!
Nicely detailed
Hello Matt, do you have a video on the dismantling and assembling of the CZJ sonnar 135mm Zebra? Or is it similar to the 50mm? My focusing ring is very stiff and has some kind of clicking sound when turned. Thank you, Cheers!
Great tutorial thank you so much for generosity to spend the time on showing us. Is the 2/Pancolar for Exakta VX1000 much different?
Hello, thank you for the video. Are these instructions relatable to same model but 135mm (C.Z. Jena Zebra f3.5 135mm)?
I fixed it! Thx for your video!
Brilliant ! Thanks for sharing
Good video. I'm struggling with the ball bearing that makes the aperture stops click. can anyone suggest a way of getting it in?
Very good video! Thank you! Do you have by some chance video for disassembling of another lens - Meyer-Optic Gorlitz Trioplan 100 2.8 Exacta? Is it very different than this one?
Hi great video.
I recently got one of these lenses and took it apart to clean the helicoid which was horrid to use. When it came to reinstalling the focussing helicoid I matched up the guide so it was aligned. However after putting it all back together the lens isnt in enough and when I focus close the lens assembly falls out. It stops at infinity. Please help, What am I doing wrong
Any advice on the aputure blades getting stuck. I took it partly apart and see that when the aperture lever is pulled it often sticks around the f5.6/f8. Would this be a blades or the lever itself sticking? Any help appreciated.
It depends. I'd try investigating the lever first because it is easier to repair. Usually though, it's the blades. Oil is the typical cause of the blades growing sluggish or getting stuck entirely. Even small amounts of oil can cause this. That's why I took apart and clean the diaphragm in this video.
If there is oil on your blades, you can try cleaning them super carefully without removing them from the housing, but I recommend taking apart the diaphragm and cleaning the blades individually with a bit of alcohol, like I show. This is generally a pain, but this particular lens is not that bad.
Hope that helps. Good luck.
Very good video both for quality of video himself that for tutorial
Hello. I also do not have 3 screws on the front side. Instead of them there are 2 deepenings and I do not understand how to unscrew them there !!!
Good for aperture stuff but could do with more details (alignment warning before disassembly) of inner and outer helicoids.
Cleaned all up, aperture ctrl fine, focus very tricky to get right, either inner helicoid falls out or gets jammed other (camera) end.
THX!
I have two of these now, both stuck wide open, one worked for a while and decided to follow the other almost as if the problem was contagious. I essentially got one free with a Spotmatic SPII as the seller just bundled it with the camera as a defective lens, I've got an excuse now to start opening up lenses and seeing if I can rescue them This one looks tricky to start with I don't think I'll go quite as far to dismantle the aperture leaves and total disassembly, but what can I lose. Another 135mm Soligor that has a 'slow aperture' I found at the bottom of a box of junk in a thrift store that may be just a straight forward clean.
The main reason I want to do this is if I'm ever confident enough I need to have my Zeiss 80mm Planer for a Hasselblad repaired as it sticks below speeds of 1/30, I can't justify the repair costs as it's as much as finding a replacement on eBay. It's not oil I think, perhaps a timing mechanism as there is a faint clockwork whirring. Speeds above 1/30 are fine.
Having said that, if I'm to perform CLAs on my lesnes the clean and the lube seem doable I guess, I presume the adjust will need a metering tool of some kind to check speeds and wot not?
You, along with a user called mikeno62, are teaching me a lot.
Thanks.
Wow, great work, super datailed video! Gonna think twice before messing wth my Zebra now =) Thanks a lot!
Mine has slightly different construction, though, some redudndant parts left after reassembly haha)
I have a slightly newer, but similar version, from 1963, with no zebra stripes, and only Jena on the name ring, no “ Carl Zeiss”.
But in the rear black outer ring, there are no screws holding it to the lens body, so do you know how to access the rear mechanicals, as my aperture is completely frozen full open......
Great video, and easy to follow, if I can get the back open to hopefully clean the aperture w/o taking it apart?!
Thanks you!
Can u do film about Biometar 120 disamble?
At 26:11, you have the tiny metal rod that controls the lever (it has a spring on it). During disassembly, this rod with the little plastic part that controls the lever came lose, and I can't seem to get it back in. Do you have any clue on how to fix that?
Heya Andrew, came back to this video for the exact same reason. Not sure if you fixed it or came up with a solution. The easiest solution I fount was taking out the diaphragm. This gives you far more movement and space to work with. Anyway hope it all worked out for you in the end. Cheers
Hello guys! Does any one of you knows if we need to grease/lubricate the focus ring after cleaning it?If so which one should I use?
Yes you will, I use white lithium grease.
Thanks for the video, Matt! I'll haveto clean my unit because of dirt and small fungus in the lens, but the back element won't come out like you described at 3:40. Any idea? Thank you in advance!
+Toni Jover Nevermind, already figured it out. Turns out I've got fungus between the two cemented glasses :-(
I have a Carl Zeiss Jena Tessar 2.8/50 with Praktina mount. I got it for $10 even if the focus ring was bent. I thought I could repair it but other problems arose. The aperture ring doesn't work, I assume someone removed the screw that holds it in place before putting it back in place. Yes, there's a screw on the aperture ring...I tried unscrewing it and screwing it again with the ring in a different position but can't get it to work. Considering their complicated designs, I'm scared to disassemble it completely and probably never be able to build it back up again. Do you have any idea how to fix this issue?
Hi Matt, great video. Do you know if the diaphragm of a Jena lens could be swapped for the diaphragm of another Jena lens with a different number of blades? I am considering the purchase of several Jena primes of different focal lengths for a project and I need them all to have a consistent number of aperture blades for lighting effects. Any pointers greatly appreciated! Thanks!
Could you make a video or give some hints on how to repair a Carl Zeiss Jena Tessar 50mm f/2.8 M42 Silver version 1Q? I got found one that has the focus ring really stiff but the bottom side is way different (no screws at all).
Thank you in advance.
Ok, if I ever come across one that needs repair, I'll be sure to post a video.
Hi, I have zeiss Jenna tessar 2,8/50, the one previous to this one (all metal), and the aperture is stuck at 2.8 and when I put my lens on my camera, my camera won't fire, I do think the aperture pin is bent, do you have any ideia how can I fix it?
I just got a Jena 1.8/50 and the aperture was as you describe. only barely working, and only when the pin was pushed in. I opened it up and found that one of two springs had snapped. I replaced it with a spring that seemed to be about the same and it worked out well. :)
Gard Hagen oh thank you! But can't seem to open the lens, there's only one screw and when I unscrew it, nothing happens (my lens has a all metal body)
Awesome vidéo, aaawesome!
Hello and thank you for this video.
I bought an old tessar 50mm f / 2.8 seized and whose diaphragm no longer works I managed to disassemble the rear and soften the helicoid, on the other hand it was impossible to remove the front cover by friction to access the screws Do I have to drill 2 holes to span it or is there another solution? Thank you and well done again
Hi, I have this lens just with a stiff focusing ring, would i be able to clean and lubricate it by accessing it from the front, or would i have to follow all the steps up to about 9:30 when you remove the track? thanks
It depends on what exactly is wrong with the lens. In the most simple case - the focusing mechanism really does just need some lubrication - you can just go in from the front of the lens to get the stage around the 6:00 mark in the video. This exposes the top of the helicoids down inside the lens, allowing you to clean those our and add new lubricant. That may be enough, and is worth trying first.
Then there's the case where the focusing mechanism is gritty feeling. This means there may be debris inside the helicoids, which requires a more thorough cleaning. In that case, I recommend removing the focusing mechanism completely, cleaning out all existing lubricant, and then applying a small amount of new lubricant.
If the mechanism itself moves fine, but the focusing ring itself is still stiff, then you'll have to investigate what exactly is causing the friction. I'd start by going in from the front of the lens because it's easier to access, but you likely will have to take the lens further apart to figure out what is wrong.
Hope that helps. Good luck.
thanks! lets see how i get on
Thanks for this info. I saw this lens in the local second-hand photo store and thought it could be interesting to play with it, but the focusing ring on that copy is behaving strangely. It is very stiff when focusing from far to near, but can rotate freely going from close to far. Will buy it tomorrow and try to repair, because it produces quite interesting bokeh and is pretty sharp for a 10 euro lens :)
Can I use this video to repair the Aus Jena 50mm T2.8 lens? It's an Exakta mount, but looks very similar to the lens in this video. The focusing ring is very stiff.
@@barmalini I just bought one of these and I have the same problem. Did you ever figure out what the problem was? Except for that one thing, the lens works perfectly, I love it. I paid $5.00 canadian for it.
That is one complex MoFo. My early 1960s Jena Tessar does not have the 'aperture blade/pin' mechanism. But a lot of my other vintage lenses do. The pin aperture style lenses, became common the 1970s.
Hi, great video! I have an 'aus Jena' T 1:2.8 f=50 lens with zebra pattern. Must be a CZ from the early period. It's broken and not complete. For starters, the aperture pin is missing. Will it work without? Rest seems pretty OK. Gonna run your video and work along. At the moment it is two parts: backside and frontside and split at the helical coil.
I got such lenses and have a question:
they looks pretty old, and have traces of mushroos guess (inside, looks like frost drawings on the glass).
i disassembled them all, cleaned small lense, cleaned front glass piece from both sides, but, as i see, there are traces INSIDE this front glass piece :|
Do you have some ideas and recomendations should i try to clean inside or just let as is?
i seriosly don't know how to dissemble this "front glass piece".
Mines is aus JENA, 8333868.
Excellent. Thank you.....!
Thank you bro!!!
good video, a brilliant job, way better than mikeno62 does it!!
thanks for talking to us and explaining how the lens works, and for not time lapsing the whole thing.
Hi Matt, would you be able to make video how to clean and assembly Carl Zeiss Jena Tessar 50mm F2.8 Aluminium version. I have 2 of these lenses and I can’t put them back together.I know there is a lot of people having the same problem.These lenses have very stiff focusing ring therefore can be found for good price on ebay but its very difficult to assembly them after disassembly.
I'm overhauling one of these, the lock ring at front was so completely seized I had to drill two small holes, even then it had to be tapped loose, wouldn't turn even with the leverage from the drilled holes. all the slotted screws undid easily though.
Nice video... but I notice you did not use the correct screwdriver blade sizes on the screws. The screwdriver blade should span the full width of the screw head slot.
Anyone who can reappear this from first time and put it back together is Avenger 😂🙏🏽
Thank You for the great Video...... Did you lubricate the helical surface? Was wondering what was used to do that.....
I used a few dabs of white lithium grease to smooth out the focusing. You don't need a lot.
Very good video, My first attempt at lens servicing, but, as I only paid $30 for this lens, if it ends in the trash, it was a good learning experience. It may go that way as I have a simple problem - on re-assembly, I am unable to thread the lens assembly into the focus collar. The helical threads do not want to mesh. I know patience is the watch word when doing this, but I have spent alot of time without success. I'm trying to thread the bottom edge of the lens assembly helical (where there is a shallow cut out to provide access to the aperture spring, screws, etc.) into the front edge of the focus collar helical thread. No luck. As an experiment, I flipped things around and tried threading the front edge of the lens assembly helical into the lens collar from the rear, and it went in like butter. I did it several times with very little trouble finding a set of teeth that meshed (there were several alternative starting points that worked.). So it seemed that the threads are not damaged. One odd thing when I did this - I could only spin the lens assembly ahead until the top edge of it's helical thread was even with the top edge of the helical thread in the lens collar. I thought I could continue and it would rotate right out the end of the collar. This is long winded but hopefully someone may have a suggestion. Thanks in advance.
HI WHY DO U HAVE TO USE white lithium grease
????
Hi, ok so I'm fucked. I took of the back plate of my pancolar 50mm 1.8 copy and a tiny metal ball fell out, i have no idea where to put it back lol. Could you help me? :D
***** Ah wait I see those tiny balls are used for the aperture ring ;) though I see I have only two instead of the whole row
Is a radioactive lense too dangerous to use.Im reading conflicting stories
I don't think so. And you always have a backup eye if worst comes to worst...
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hello
i got a copy of this lens aus Jena ddr 50 f 2.8 this structure lens i guess is different from carl zeiss jena 50 f 2.8. i dissemble it because there is a problem with aperture blade it actually got stuck and doesn't work fine
my main problem is with the front part it seems different with carl zeiss and it is one piece ( carl zeiss's one has a name ring and after screw it you can see 3 pin but this one seems doesn't)
if i want to reach aperture blade i have to open this part i guess. can you help me about my problem. how can i fix this model's aperture blade
this picture belongs to the front part
8pic.ir/uploads/3_07aa6.jpg
8pic.ir/uploads/1_d924e.jpg
i am glad to see your opinion.
thanks in advance.
JESUS FUCKING CHRIST !!!! This goddam aperture assembly does NOT want to screw back in the bottom part. I've been at it for more than a couple hours now , it went in ONCE but not in the right spot! kill me now...
Update: 5 hours later and I'm still fighting with this goddam lens... The fucking notch in the thread is making it impossible to align the 2 pieces properly... I think I'm gonna go to bed for tonight. I have been defeated.
Update #2: I was able to remove the thread from the bottom part (the one with the lever for the aperture) using a spanner wrench. and I tried screwing it in all direction (4 different ways) and something is definitely blocking the progress. When trying in the way they're supposed to be but from bottom up it gets stuck right as it reached the ident in the thread (where the mechanism is). I'm starting to think my thread is fucked somehow. Tried looking with a magnifying glass but can't see anything, I'll need to use a microscope...... I hate this fucking lens, IQ better be good...
A brain surgery! It's too scary! I'd rather throw the lens away rather than disassemble and re-assemble it again 😰
NOPE