Zuiko 50mm f1.8 strip?

Mad_Sunday · Joined: 23 Jun 2009 Posts: 24 Location: Staffordshire, UK

Hi,

I have a couple of these great lenses but one needs a strip and a clean. Has anyone got the info on how to strip, clean and re-build these Olympus lenses?

Pete

Attila · Expire: 2025-11-18

Modern lenses like this one perhaps not easy. Many of them has glued elements if fungus inside between two tags mostly un-clenable at home.

dnas · Joined: 14 Nov 2008 Posts: 488 Location: Japan

I take it you mean the OM Zuiko Auto-S 50mm F1.8? (the small OM, manual focus lens??)

This lens is easy.

It is quite prone to having sticky aperture blades. The sticking is not so much on the blades themselves, but on the follower rings, and around the sliding machanism. Various surfaces that get coated with grease that has melted onto these parts.

Undo the front plastic cover using rubber friction.

The front elements are held in using 3 screws. Remove these and the aperture ring also comes off. Don't lose the ball bearing.

Remove the mount. Lift it off carefully and lay aside the two side "buttons"(one is the unlocking button, while the other is the sperture stop down button). Lift the two black aperture follower levers out together(and the silver part underneath), which are joined with a spring. If these have grease sticking them together, you may need to unclip the spring.

You now have access the the rear element group. Unscrew the rear group, and the rear element will come away. This also unlocks the next element which will just drop out, if you overturn the lens. Be careful not to do this accidentally. You now have access to the aperture assembly. You can unscrew 3 screws, lift the plastic and you have access to the aperture blades.

Clean the parts on the mount end, as these will often have melted grease on them. At this stage, you can either attempt to flush the remaining parts(in the aperture area) with ronsonol(etc), or remove the aperture assembly and clean each piece in turn.

When you reassemble, slide the aperture back and forth, so that it rests just near the "elbow" of its running slot. This will make it easier to reassemble.
When you put it back together. there is only really one trick.
Once you replace the two black aperture followers, before you replace the aperture stopdown button, push the silver part under the two black followers in, and seat it properly as you do so. Then replace stop down button, then the locking button.

Oh, and by the way, these lenses seem to be quite resistant to damage from fungus. I recently had one with a nasty concentrated point of fungus, surrounded by vicious looking tendrils, but it all cleans away with no damage to the coatings or glass at all !!!!!

marty · Joined: 09 Apr 2009 Posts: 767 Location: Italy

Here the exploded diagram of the F.Zuiko Auto S 50mm f1.8 : http://olympus.dementia.org/Hardware/PDFs/50mm_f1.8.pdf
Regards, Marty.

Mad_Sunday · Joined: 23 Jun 2009 Posts: 24 Location: Staffordshire, UK

Thanks both for the info. There are some marks inside the front element so maybe I wont have to go too far in.

Pete

dnas · Joined: 14 Nov 2008 Posts: 488 Location: Japan

Mad_Sunday · Joined: 23 Jun 2009 Posts: 24 Location: Staffordshire, UK

I will have to remove a dent in the filter thread before I can unscrew the front cover Sad

I'm working on making a dent remover first then I need to sort the rubber friction tool. The stop down button is missing, although I don't need this it would be nice to replace it while the lens is apart, can I order a new one from Olympus? Thanks for the help, I'll get back with the outcome.

Pete

DavidLame13 · Joined: 03 Jun 2013 Posts: 11 Location: France

Hello dnas,

I'm following your instruction to clean a Zuiko MC 50mm 1.4, which I believe have the same construction.
My lens have a big dust inside the rear element, now I'm at the setp "the element will drop out", but the dust is still further inside.
Could you please show me how to remove the next element?

Thank you,