Repairing stuck aperture on a Pentacon auto 50mm F1.8 Multi Coated lens.
HTML-код
- Опубликовано: 7 дек 2020
- Patreon ► www.patreon.com/user?u=57434418
Repairing stuck aperture on a Pentacon auto 50mm F1.8 Multi Coated lens (M42).
This lens from Pentacon has a stuck aperture mechanism. Watch the whole video so you don't have to disassemble parts that don't need to be.
EP16
Music:
Destination Unknown
By : Ugonna Onyekwe
New Horizons
By : Futuremono 
Хобби
Just wish to add a couple of small points:
This lens started life as the Meyer Oreston, went through several versions. Their mechanical constructions differ from each other, sometimes significantly, so the method for fixing this final "Multi Coated" version would not apply to an earlier version.
Over time, the grease applied by many German manufacturers would have failed, and made the lens operation progressively more difficult. The lighter part of the grease distillates and covering the iris mechanism would make its action sticky, but the heavier component would cause even more problems. When I attend to one, I routinely take the focussing helicoid apart, clean off all the old grease and replace with modern grease.
Once I learned what the issue might be from your video, I was able to fix mine without even taking apart the lens. Just focus down to the minimum distance (0.33m) - this creates enough of a gap around the rear element that you can access the stuck lever with a small thin instrument, and clean the inner part of the hinge spring. Of course, on a "more stuck" lens this might not work, but I'd say it's worth a shot in case someone is too afraid (or lazy) to open their lens.
I just bought a Praktica LTL 3 which came with the Pentacon Auto 1.8/50 Lens all for £10?!
And I went to have a look etc at it and opened up aperture and boom stuck. This comment! Saved me a lot of issues. Kept getting stuck and I just decide to keep working it
Opening and closing it then turning the putter ring back and forward till it got stuck and then release it how your comment said, kept doijg for about 10 mins to get any dried up oil etc mixed and joint lubricated and happy days it’s all working! So thank you!!! 🎉
@@OQWO I'm happy someone found my comment useful!
Saved my lens. You are amazing.
👍fixed mine just like that
I have the exact opposite problem. I also went about it the wrong way, as you first did.
I spent ages tinkering with the auto aperture actuation mechanism at the back, only to realise that the problem is slightly sticking aperture blades. It wouldn't be a problem, but as you know, it's indirectly operated by a spring, and the spring just isn't strong enough to overcome the tiniest resistance.
It works fine until I face the lens downwards, then it is jammed fully open until I take it apart again.
Thanks so much, I had exactly this issue, and whilst it may have taken me 3 hours, I fixed it thanks to you!
非常有幫助的視頻， 教你如何修復光圈
Zen and the art of photographic lens repair!
Thank you for the tutorial! Just fixed mine! Cleaning the sticky blades did it! ✨
Very nicely done. You are very delicate as it should be ! Thank you !
I just bought a m42 adapter to play with some old lenses from my mom. I was very excited about this f1.8 pentacon, but the aperture was stucked and thank to this video I was able to fix it. Thank you very much
There is a tiny spring in mine. Not sure if it should go behind metal ball bearing or in front
It fell out when I was disassembling it. It was a bit bent on the top, I dropped it so, I hammered it back into shape and now I can’t figure out where this spring goes
Thanks very much indeed for this - I swerved the bit about the blades and took the Mount off first, sure enough the lever was stuck. Thank goodness I didn’t have to take the blades out!
Had to make it twice couse the first time did not clean well the blades and stuck again. Just finish to assembly and all good. Made my day again👍
Thank you! Just fixed the aperture on my lens with help from your video :D
Thanks I lot. I just fixed my aperture ring!
thanks a million mate! Following your video I was able to repair my pentacon!
I almost took it apart, but then I checked the pin (0:51) and realized I was on Manual mode ( I have the Pentacon 29mm f2.8), and this helped me out! I got so scared that my lens suddenly broke, but it was just a minor mistake thanks to this guy. Try this before you actually take apart your lens - It may save you a lot of excessive work. :)
Thanks man, done
Merci beaucoup ,c'est super j'ai le même problème je vais pouvoir réparer grâce à vous ,j'adore cet objectif qui est vraiment très bon.Thank you very much
To hopefully save others time, check the auto/manual mechanism first - turns out my issue was a stuck (dried out?) auto mode - I did the entire teardown, wiggled that mechanism a little and it started working haha. Was worth going through it anyway, was fun reassembling the aperture blades.
Thanks for a great tutorial :) Saved me a couple hundred dollars!
Всё чётко и понятно,респект!
Very helpfull. Just fixed mine following these steps. Thank you!!
Glad it helped!
You made my day👍👍👍
Same problem again😭. Thanks i did it twice. Will disable it again👍
ive unstuck aperture blade by just applying isopropanol to the blades with a paint brush then using the level inside the lens to open and closes them a few times, then used a cotton bud to soak up the oil/isopropanol mix on the blades. Did this a few time and aperture blades work fine. I myself just didn't fancy taking the Aperture mechanism apart
Я буду пробовать❤
This is a scary movie!
Have an earlier version Jena lens the 50/1.8 Pancolar with similarly unmovable aperture. The aperture pin is fully loose in/out however no blade action to speak of. This video will help me get it fixed. Thank you.
I hope you get it fixed!
Thanks for the video. So possibly it could've been fixed with just taking off the rear of the lens and clean+lube the lever system? I have one that's stuck, but taking off the front and blades isn't something I want to attempt myself. The rear looks manageable though.
Yes, I should have checked the aperture linkage before removing the aperture blades. Because it is common for these lenses to build up oil on the blades, I wrongfully diagnosed the lens. Please check the linkage first (by removing the rear mount) and if that doesn't fix it, the aperture blades may need to be cleaned.
I just received a 135/2.8 Pentacon where the aperture blades moved erratically, so that they would sometimes not close, and sometimes they would close partially, so that the true aperture would be bigger than the set aperture. I removed the four screws at the back to expose the arm which pushes the tab the operates the aperture blades (the arm is seen at 9:05 in this clip). I found that the blades operate without any friction, so there is no reason to disassemble them. But the arm moves freely also. So, if everything moves without friction, why does it not work? There is a super tiny screw at the base of the arm which controls the extent of the motion of the arm, and I opened it by 3/4 of a turn, and that seems to have fixed the problem. Essentially, the arm now pushes the tab that operates the blades a little harder.
It must be a common issue. If memory serves, I've had the exact same problem on at least three Pentacons, a 1.8/50, a 2.8/135 and a 4/200.
Hey, thanks so much for the video. I have an older version of this lens (electric), and for some reason moving the focus ring is also adjusting the aperture blades slightly - any ideas what may be causing that?
I am not certain, but it may be something loose inside such as the three screws holding in the aperture assembly. Also be sure it is clocked in the correct orientation. Good luck.
How to fix Pentacon lens that unscrews and separates after turning focus?
Damn, checked the lever and seems to work perfectly but I can actually tell the blades are oily by looking through the lens from the back. Works fine until I open the aperture to 1.8 and it sort of goes too far and get stuck. So let me get this straight - oily blades are bad?
Oil on blades are bad.
My lever isn't stuck it works fine when I push the button. If I manually operate the blades with the vertical rod they move. Any other suggestions? I read a comment regarding the blades could be too sticky for the strength of the spring? It feels like there's a piece missing...the aperture ring has nothing connecting it it just sits in there.
If there is nothing connected to the aperture ring, it may be very possible that the lens has been disassembled or reassembled incorrectly.
Hi! Please tell me how to screw in the helicoid, I unscrewed it without putting a mark
Installing the helicoid, will be trial and error.
Hello, I can't remove the branding ring. I've already applied wd-40 but I can't remove it, even with the help of a rubberized cover to apply more force. Any ideas on how to do this?
You can try using rubber gloves, or something to increase friction. I would make sure the filter threads are not damaged or bent. If so, removal might be impossible.
So if I am able to move diaphragm with the pin then I need to disassemble the front?
It really depends. Oil contamination can cause the diaphragm to move slowly. But it can still function when the pin is depressed. And of course, the oil can sometimes not be seen on the blades themselves, but the rotating aperture unit itself.
you cut through the heart of the lens to fine the problem in the very rear ?
Yes.
Whats mean that M/A switch in Pentacon Auto series? I am Lumix user with 2,8/29 lens on - its pointless for me?
The M/A switch is the Auto/Manual Stop down switch made for SLR's without the Auto-stop down function. M (Manual) is chosen for stop down metering cameras. It is most likely pointless for you, as your adapter has a flange to push in the stop down pin on the back of the lens, making the switch useless.
Hii. Thank u for this video.This lens a radioactieve?
No it is not.
@@FocalReduced thank u
Nice and neat repair...liked n subbd...BUT the techno music was TOO irritating ! Better some soft lounge jazz !
Thank you. I'll try to remember that.
Hi, I have the very same lens. It works fine but the aperture ring is loosen and doesn't "tick" when rotating. Can I Fix this? Thank you!!
Yes. It could be an issue with the ball bearing.
@@FocalReducedthank you for the answer. Where should I check? Below the part on the right with two screws at 8:58? How should i place it?
Thank you so much!
The ball bearing for this lens is located between the 4 and 5 o'clock position when the lens' Index scale ring is facing upwards.