The fungus is still there. Perhaps a different UV light would have some effect.
It looks like the fungus has allready damaged the coating.
I have a Miranda 25mm lens which is/was hazy and has/had ight fungus.
I put it under the Ikea Jansö LED light for at least 2 weeks. The haze seems to have disappeared and the image in the viewfinder ist contrasty again. I need to run a film through and compare against the other Miranda lenses.
With the haze the look through view finder was very soft, also the images showed very low contrast and looked a little like "David Hamilton" image. Except that I do not have the models needed for such images :-)
Topcons and Kowas are on my watchlist for long time. But GAS was not strong enough to make me hunting for one of them.
But a few weeks ago a person I know offered a cheap bunch of cameras. Among them a Topcon IC-1 2nd model and a KOWA SE together with Canoen AE-1 and T50. All together for a price I could not resist.
I ordered the convolute together with a Flektogon 35 for my Exakta.
In parallel I found an eBay auction of 2 Topcons in Austria (IC-1 first version, and Uni) together with 28 and 135mm lens. I won the auction cheap because sold as broken.
The seller of the first packet sent me an email that he also found an Unirex and added it to the parcel :-)
Now I have 4 Topcons and one Kowa SE. The ebay Topcons work after cleaning and fitting new batteries, also the Unirex works but exposure meter seems to be off. I did not yet put a batterie in the KOWA SE but shutter works fine on all speeds.
I'm surprised about the the mechanical shutters of the KOWA and the Topcon Uni*. They run fine at all speeds after that long time, also self timer works.
Back to original topic: I'm still looking for an Olympus OM-4. prices are beyond my range now. But last week I overlooked an auction with a winning price below 50€,