Olympus 28mm f/3.5 fungus

[franglais69]

Hello all

I've read with great interest and admiration some of the threads about cleaning these old lenses.

It encourages me to define a project to clean this lens that I recently acquired.
It produces sweet images and is so light and dinky which is perfect for street carrying; For the curious, here's a good review of its performance by Alex Luyckx
So I dont want the fungus to spread any further.

I'll add that I have never attempted this kind of project before and at the moment I don't have the necessary tools.

I'll fix that as I am now bouncing off your successes and advice and its looks like fun.

Before I discovered this forum, I watched youtube videos, one concerning opening this very lens by Matt Bierner .

It shows a relatively easy workflow to open it, BUT he indicates that he wasn't able to open the rear using a spanner wrench.

In my case, the lens has fungus on the rear glass as shown here, so IDEALLY it makes sense to try to remove just the rear and clean it.

The above reviews indicate this is a retrofocus lens, maybe that means that OLYMPUS glued the rear lens elements to prevent anyone from moving them.

So as a perfect novice to such work, I'm wondering what I should do to get access to this fungus.

Some of you speak about using WD-40, isopropyl alchool, 50/50 mixtures ... to unlock threads but will any of those work to unstick this rear element if it has actually been stuck in with Loctite?

The access from the outisde is straight forward as shown, but what do you do if it wont budge at all?

I'm happy to give it a go once I buy the right wrenches and stuff.

On that point, I see different wrench designs. Some allow the points to be installed at right angles to the main frame.
This would seem to provide better leverage to help out .

Others like tjis Neewer design, just install points vertically, so I'm guessing that's less leverage.

All advice welcome

Thanks

 

[Andreas Thaler]

I would simply start disassembling from the back and see how far I get. If it is a glued lens group, the usual methods will not help.

I have both of the spanner wrenches you showed and I usually work with the lower one. Here you should make sure that the blades or tips are firmly in the recesses on the lens so that they do not slip off.

 

[Andreas Thaler]

Here is the structure of the OM 28/3.5.

http://olympus.dementix.org/Hardware/PDFs/28mm_f3.5.pdf

The two rear lenses are therefore easily accessible after removing the rear retaining ring, which has two recesses for the spanner wrench as your photo shows.

If the fungus is on the outside of one of the two lenses and has not yet etched the glass, it should be easy to remove with hydrogen peroxide.

 

[Andreas Thaler]

The above reviews indicate this is a retrofocus lens, maybe that means that OLYMPUS glued the rear lens elements to prevent anyone from moving them.

View attachment 377475

So as a perfect novice to such work, I'm wondering what I should do to get access to this fungus.

Some of you speak about using WD-40, isopropyl alchool, 50/50 mixtures ... to unlock threads but will any of those work to unstick this rear element if it has actually been stuck in with Loctite?

The access from the outisde is straight forward as shown, but what do you do if it wont budge at all?

I don't think the rear retaining ring is secured with adhesive, at least that would be new to me on a lens.

If it is, I wouldn't use acetone to dissolve the adhesive here as it could dissolve the paint.

WD-40 would be a good option, put a small amount on the threads and wait an hour for it to soak in. However, there is a risk that it will spread further across the optics and not be able to be removed if the retaining ring resists.

So I would try isopropyl alcohol, but again only sparingly.

But I think the spanner wrench has a good chance.