[mrNewt]

There is no point indeed to bring it to a repair facility... But you can always try to fix it yourself. You can try to umount the rear screw and see if you can set the blade where they should be! Lens's dead, so there is no risk trying.

Warning, use only JIS screwdriver.

Yep, thanks - I have worked on cameras and some lenses before... managed to gather some tools over the years.
I'll admit though, I usually have stayed away from the aperture blades and never actually taken them apart... or put them back together.
It will be an interesting challenge .

Agree!

Side note, if you’re in the states, pm me, I’ll be happy to play and return if you want.


Hang up and DRIVE!

Unfortunately, I am not - but thank you very kindly for offering to have a look at it .
I'm located in Canada.

[mrNewt]

As an update on this...

I managed to open up the lens and have a look at the blades.
One of them was a little bent and I had to work on it to get it as straight as possible - I guess it got bent while was in use and it came off the grooves. I then manged to assemble the blades back in place and they worked... for a little while... and then they came apart again after using the lens for a couple of tests.

I honestly have no idea why...

What I have noticed... the "helicoid" is plastic... the two halfs that are guiding the aperture blades are plastic... and there is no trace of some sort of grease or oil to help with friction over time... not sure if that is normal or not, but it seems odd that there is nothing to help with minimizing the wear down. Plastic on plastic parts rubbing against each other.

My only guess is that the plastic that is used in the key areas has loosen up, or wear down a little bit, just enough to allow for the blades to jump off the groves. Or heat/cold have affected them and tolerances are bigger now. There seems to be a little bit of play, no matter how hard you try to tighten that front ring - obviously not going overboard and stripping the plastic threads.

If the front ring is not tight enough or comes loose over time (again, it screws into a plastic sleeve basically), the blades will come off the grooves for sure. That is what keeps the guides for the apprture blades in place, tight against each other!!!
So, when you work on these lens, pay attention when you remove that front ring.

Quite disappointed with the construction of these lens .

Does anyone know if the inside of the limited lens are the same? Or they are actually using metal parts for the blade grooves and helicoid?

I have the entire green ring collection... worried eventually they will have the same fate .

[mrNewt]

Update... update...


So today I took it again apart and spent more time on it and re-checked everything. I am now more and more convinced that the main cause of the issue is loose front ring of the lens. Because of the quick movements of the blades (when mounted on camera), if the two half parts that guides and sandwich the aperture blades into place are even a hair loose, the blades will go flying off the tracks...

Anyway, a few pictures of the whole thing - leaving them here for future, if anyone might end up with same issue and needs some reference...


How the blades were inside before I opened it the first time (after I removed the core).
Everything in this, except the aperture blades, screws and front ring is plastic.





Aperture blades were just falling off before I removed the front ring...





The two guides and the mess between them - you can see the blade that was bent on the right side:





Putting things back together...





Inner core in place, back view:





Inner core in place, front view:





Everything back together - I have added 2 drops of shellac at the base of the threads. Hopefully this will keep the ring in place and it won't loosen over time...




Anyway, everything seems to work for now... hopefully will stay like that otherwise I am giving up on them .

[UncleVanya]

Great photos showing the chaos and order. Lol.

[MikeMcE]

Always use a thread locking agent. We used “anerobic liquid “sealers (fancy loctite)


Hang up and DRIVE!

[barm]

Update... update...


So today I took it again apart and spent more time on it and re-checked everything. I am now more and more convinced that the main cause of the issue is loose front ring of the lens. Because of the quick movements of the blades (when mounted on camera), if the two half parts that guides and sandwich the aperture blades into place are even a hair loose, the blades will go flying off the tracks...

Anyway, a few pictures of the whole thing - leaving them here for future, if anyone might end up with same issue and needs some reference...


How the blades were inside before I opened it the first time (after I removed the core).
Everything in this, except the aperture blades, screws and front ring is plastic.





Aperture blades were just falling off before I removed the front ring...





The two guides and the mess between them - you can see the blade that was bent on the right side:





Putting things back together...





Inner core in place, back view:





Inner core in place, front view:





Everything back together - I have added 2 drops of shellac at the base of the threads. Hopefully this will keep the ring in place and it won't loosen over time...




Anyway, everything seems to work for now... hopefully will stay like that otherwise I am giving up on them .

Hi MrNewt,

Sorry to bring this up 2 years late, and I hope I can borrow your expertise for a moment.


I have the same lens that is exhibiting severe imaging issues. I know it's supposed to be on the soft side wide open, but the out-of-focus highlights seem to be a mess as seen in the attachment with the trees.


It appears that I have some haze on one of the inner elements (along with some dust). It looks like it might have been oil from the aperture blades that lightly fell on the lens, given that there's a little hole where the aperture blades would be when the camera is out of the body and resting.


In your estimation, would a disassembly and cleaning of the lens assembly be a doable feat for a hobbyist who's good with little parts, or is it better if I take it to a shop?

Thanks!

[mrNewt]

Hi MrNewt,

Sorry to bring this up 2 years late, and I hope I can borrow your expertise for a moment.


I have the same lens that is exhibiting severe imaging issues. I know it's supposed to be on the soft side wide open, but the out-of-focus highlights seem to be a mess as seen in the attachment with the trees.


It appears that I have some haze on one of the inner elements (along with some dust). It looks like it might have been oil from the aperture blades that lightly fell on the lens, given that there's a little hole where the aperture blades would be when the camera is out of the body and resting.


In your estimation, would a disassembly and cleaning of the lens assembly be a doable feat for a hobbyist who's good with little parts, or is it better if I take it to a shop?

Thanks!

If you've never taken a lens apart and successfully put it back together, there is always a chance to ruin the lens.

That being said, this is not a complicated lens - is a prime (primes are usually much simpler to work on). If you are patient and go slow and take your time, is not that complicated.
This one is even simpler since it doesn't has any aperture stop ring.

Take lots of pictures and be careful with those aperture blades.

[barm]

Thanks for your response mrNewt. I'll give it a go in the coming weeks during the holiday season.

Cheers!