Thank you for the help. I just cleaned mine yesterday and the aperture can close again. I couldn’t get the 3 screws out of the Mount side and tried without and that also worked for me. Just removing the from element and the ring holding the blades
Thank you so much for this video. Ich was struggling so much to reach the front of the aperture. Only due to your video I finally got know how to open the front. It needed a lot of force on my lens but now it works flawlessly again.
Thank you for making this video. I picked up a Mamiya 645 with a couple of lenses, but it turned out the aperture for both lenses did not work. The aperture just stayed wide open. I have never repaired a lens before, but thanks to your video, I was able to easily fix my 80mm f2.8. I'm going to try the 150mm f4 next, and I have a 70mm 2.8 leaf shutter which is acting odd, but I may have to research more for that. Particularly where the cost of repair is higher than the value of the lens, you have saved this lens by sharing this information. Thank you, thank you, thank you.
had the same exact problem with the same two lenses... hmmm. for some reason though my aperture ring locks up when i put the rear part back on. still can't figure it out.
Wow, I am so glad I found this before going ahead with Todd's method. He goes in from the back and pops like four clip rings and removes springs and glued parts. He does get the interior cleaner, but really risks dirty elements and alignment issues. I can do your method without sweating. Thanks!
Why was it necessary to remove the mounting ring when you were able to reach the aperture mechanism through the front? I will be attempting this procedure soon.
@mikeno62 Hello, I cleaned 3 lenses this way now, so thank you very much :) With the latest one, the aperature closes down normally, but when expanding back it doesn't fully open (stops around f/4). Should I get a new spring?
Hi mikenos! Do you know how can a disassembly a Mamiya 45mm 2.8 ? The frontal part is stuck. I don’t know if I can rotate like this lens you are working or if i can rotate the frontal ring with rubber... Please, help me. Thanks so much for your channel. Best regards from Brazil.
Fantastic, I have the same lens and the iris appears to be stuck in the open position regardless wether it is set to manual or auto any idea what might be causing that please?
+northstar1950 Well, it sound's like there is oil in the aperture system in your lens, so this film shows the way to solve that problem.. REMEMBER to read the "about" to get more info.
Another question: Did you have any trouble getting the screws out of the mounting ring on the rear of the lens? Mine seem to be especially tight. The screws head slots are still fine, but I've ruined 3 precision screw drivers so far on them. Any suggestions? I know to go slow starting out on them, but they just wont seem to budge at all and I'm wearing away the skin on my palms working them.
Hi Tom I did not have any trouble getting the 3 screws off, maybe someone had use the red locktite screw lock (the hard one...., NOT for those small screws)). Are you sure you use a JIS screwdriver or just the normal PH00 screwdriver, it's because you will destroy the screws if you use a normal PH00. To prevent the screwdriver to be ruined, you can do the same as I do, make my own JIS out of a normal PH00, just file the pointet tip so the screwdriver will fit perfect in the screw head. If the screws are still very tight, you can try to heat up the screw head with a solering iron just on the screw head, it will probably soften the screw glue or whatever they have used to lock the screw (just an idea) If you can find some of those very sticky gloves it will give you a much better grip on the screwdriver.
Hello and a healthy new year. I got recently an Mamiya Sekor 80mm 1.9 lens and sadly with oily blades. Any advice to get it fixed and ready for the first roll? Would love to hear your opinion on that particular lens. Thanks in advance, Richard
Happy New Year :-) Well, I haven't work on the Mamiya Sekor 80mm 1.9 so I don't know, but I guess it's maybe the almost same way to open it like the Mamiya Sekor C 80mm 1:2.8 in this film. Greetings Kenneth
@mikeno62: thank you for that video, it helped me a lot to reach and clean the blades of my 80mm. @Tomáš Kušnír: I just repaired my Mamiya Sekor C 45 mm f/2.8 N. Like you I wasn’t able to find any information about it and had to try it by myself, so I share here my experience. 1- to reach the blades, you have to work it by the front only; 2- unscrew the name plate; 3- dismount (3 screws) the front tube in which was the name plate; 4- DO NOT unscrew the 3 screws beneath: these maintain the position for the focus of the inner tube with the front one moving in the helical; 5- unscrew by hand the front bulbous lens element; 6- unscrew with a spanner wrench the complete lens element beneath by its outer ring in bare aluminum; 7- now you have access to the diaphragm; release the spring; 8- remove the brass snap ring; 9- remove the disk commanding the aperture; the blades are beneath; 10- take pictures of each step. You shouldn't have to dismount the back of the lens (I had to because I had other problems there), but take care, when mounting things back, with the disk commanding the aperture: its finger at the back has to go to the right place in the small triangular and rotating piece, mounted on the back of the tube and almost invisible. Play with the aperture ring on the back of the lens, in M position, and you should see that piece move through the hole for the finger. Test it after putting back the snap ring and the spring to check if you put the finger in the right place. Hope this helps. ;-)
I could send you mine for you to clean the blades and make a video and we could kill two birds with one stone. But on a serious note I really appreciate all the videos you do! Very helpful! Thank you!
Thank you for the help. I just cleaned mine yesterday and the aperture can close again. I couldn’t get the 3 screws out of the Mount side and tried without and that also worked for me. Just removing the from element and the ring holding the blades
I found this today - exactly what I was looking for, you helped me bring life to a very steaky lens!
Thank you so much for this video. Ich was struggling so much to reach the front of the aperture. Only due to your video I finally got know how to open the front. It needed a lot of force on my lens but now it works flawlessly again.
Thank you for making this video. I picked up a Mamiya 645 with a couple of lenses, but it turned out the aperture for both lenses did not work. The aperture just stayed wide open. I have never repaired a lens before, but thanks to your video, I was able to easily fix my 80mm f2.8. I'm going to try the 150mm f4 next, and I have a 70mm 2.8 leaf shutter which is acting odd, but I may have to research more for that. Particularly where the cost of repair is higher than the value of the lens, you have saved this lens by sharing this information. Thank you, thank you, thank you.
had the same exact problem with the same two lenses... hmmm. for some reason though my aperture ring locks up when i put the rear part back on. still can't figure it out.
For anyone interested, this also works as reference for the 55mm f/2.8, they're built practically identical
Mike, just followed your video to clean my Mamiya Sekor 80 2.8 glass. I did not went up to the blades, but it was super useful. Thank you.
I've used your instructions to clean the aperture blades of a Mamiya Sekor C 1:2.8 f=55mm.
Thank you for sharing.
Regards.
Wow, I am so glad I found this before going ahead with Todd's method. He goes in from the back and pops like four clip rings and removes springs and glued parts. He does get the interior cleaner, but really risks dirty elements and alignment issues. I can do your method without sweating. Thanks!
Thanks for making these videos. I was able to fix my lens. Keep up the good work.
Thanks for posting this, just finished fixing my lens, aperture works perfectly now.
Great video Mikeon62! I've got a beautiful 80mm 2.8 that should soon be working like new. Thank you.
Thank you so much! I just did it, step by step and it was really easy.
Why was it necessary to remove the mounting ring when you were able to reach the aperture mechanism through the front? I will be attempting this procedure soon.
@mikeno62 Hello, I cleaned 3 lenses this way now, so thank you very much :) With the latest one, the aperature closes down normally, but when expanding back it doesn't fully open (stops around f/4). Should I get a new spring?
I have heard if you put lenses in the washing machine they will be brandnew. Is this true???
A question, is it easy to get to the focussing mechanism too this way? My aperture is fine but the focussing is inconsistent and a little 'gritty'.
can the front just come off without removing the back first? i just need to clean the front element. thanks!
Hi mikenos! Do you know how can a disassembly a Mamiya 45mm 2.8 ?
The frontal part is stuck. I don’t know if I can rotate like this lens you are working or if i can rotate the frontal ring with rubber...
Please, help me.
Thanks so much for your channel. Best regards from Brazil.
hi, dis you find the answer? The front of my 80mm is stuck too.
Fantastic, I have the same lens and the iris appears to be stuck in the open position regardless wether it is set to manual or auto any idea what might be causing that please?
+northstar1950 Well, it sound's like there is oil in the aperture system in your lens, so this film shows the way to solve that problem..
REMEMBER to read the "about" to get more info.
Thanks mikeno.
Worked, But now my lens only functions on M? any advice?
Another question: Did you have any trouble getting the screws out of the mounting ring on the rear of the lens? Mine seem to be especially tight. The screws head slots are still fine, but I've ruined 3 precision screw drivers so far on them. Any suggestions? I know to go slow starting out on them, but they just wont seem to budge at all and I'm wearing away the skin on my palms working them.
Hi Tom
I did not have any trouble getting the 3 screws off, maybe someone had use the red locktite screw lock (the hard one...., NOT for those small screws)).
Are you sure you use a JIS screwdriver or just the normal PH00 screwdriver, it's because you will destroy the screws if you use a normal PH00. To prevent the screwdriver to be ruined, you can do the same as I do, make my own JIS out of a normal PH00, just file the pointet tip so the screwdriver will fit perfect in the screw head.
If the screws are still very tight, you can try to heat up the screw head with a solering iron just on the screw head, it will probably soften the screw glue or whatever they have used to lock the screw (just an idea)
If you can find some of those very sticky gloves it will give you a much better grip on the screwdriver.
Hello and a healthy new year.
I got recently an Mamiya Sekor 80mm 1.9 lens and sadly with oily blades.
Any advice to get it fixed and ready for the first roll?
Would love to hear your opinion on that particular lens.
Thanks in advance,
Richard
Happy New Year :-)
Well, I haven't work on the Mamiya Sekor 80mm 1.9 so I don't know, but I guess it's maybe the almost same way to open it like the Mamiya Sekor C 80mm 1:2.8 in this film.
Greetings
Kenneth
Hi @mikeno62, do you have any experience with the 150mm f4 Mamiya C?
+Daniël Kersbergen No, not at the moment..
I tried removing the front ring this way on my sekor C 45/2.8 N but it didn't come off.. any ideas? Thanks
I havn't worked with the 45mm/2.8 N.
I guess I have to try it myself then. Thanks for the reply.
I got one with oily aperture,,diferent construction,have to remove ring from front side of lens,,behind text ..
@mikeno62: thank you for that video, it helped me a lot to reach and clean the blades of my 80mm.
@Tomáš Kušnír: I just repaired my Mamiya Sekor C 45 mm f/2.8 N. Like you I wasn’t able to find any information about it and had to try it by myself, so I share here my experience.
1- to reach the blades, you have to work it by the front only;
2- unscrew the name plate;
3- dismount (3 screws) the front tube in which was the name plate;
4- DO NOT unscrew the 3 screws beneath: these maintain the position for the focus of the inner tube with the front one moving in the helical;
5- unscrew by hand the front bulbous lens element;
6- unscrew with a spanner wrench the complete lens element beneath by its outer ring in bare aluminum;
7- now you have access to the diaphragm; release the spring;
8- remove the brass snap ring;
9- remove the disk commanding the aperture; the blades are beneath;
10- take pictures of each step.
You shouldn't have to dismount the back of the lens (I had to because I had other problems there), but take care, when mounting things back, with the disk commanding the aperture: its finger at the back has to go to the right place in the small triangular and rotating piece, mounted on the back of the tube and almost invisible. Play with the aperture ring on the back of the lens, in M position, and you should see that piece move through the hole for the finger.
Test it after putting back the snap ring and the spring to check if you put the finger in the right place.
Hope this helps. ;-)
how similar is this to the build of the 55mm 2.8?
Hi Tom
I haven't yet work on it, but I guess it is almost the same construction.
If I come across one, I will make a film about it.
I could send you mine for you to clean the blades and make a video and we could kill two birds with one stone. But on a serious note I really appreciate all the videos you do! Very helpful! Thank you!
can the front just come off without removing the back first? i just need to clean the front element. thanks!
Would like to know as well.