Fungus?

[A McEwan]

Hi. I wasn't sure where to post this, so here it is. I fished out my TAL 6x30 finder from cupboard where it's lain for the last couple of years, and found this. Is it, as I suspect, fungus? If so, is it completely on its way out now?

Ant

[Alien 13]

Dont think its fungus, looks more like moisture has got into a cemented element.  I had a lens like this and put the element into warm soapy water for a few days and it separated, I then cleaned off the "cement" with some alcohol then refitted the lens assembly using a thin strand of copper wire around the edge to "air space" it, worked fine after..

Alan

[A McEwan]

Thanks. I must dismantle it and have a closer look then. The view through it is actually ok (in daylight anyway).

Ant

[dyfiastro]

This may sound excessive but I have just recently treated fungus on a lens (not that bad).
I used an mild IPA solution and allowed it to sit for a few hours and then rinced off.
This was followed by a mild peroxide solution to kill off any remaining fungus. I also wiped down the inside of the tube.
This was followed by a further rinse with a combination of IPA and distilled water.

There is now no signs of fungus on the lens and it did not effect the coatings either.

[A McEwan]

IPA? Er... India Pale Ale?

[tooth_dr]

2 minutes ago, A McEwan said:

IPA? Er... India Pale Ale?

Isopropyl alcohol 

[John]

I think that is an issue with the cement holding the lens elements together as Alan / Alien 13 says.

I've seen fungus on a lens and it looks different. More like this:

[A McEwan]

Good, I'm relieved it's probably not a fungal problem. I will take some time at the weekend and open it up and follow the advice above. It's a nice finder and it would be a shame to have to lose it.

 

[philj]

Nah thats not fungus Ant. Its the 2 elements separating, maybe moisture related but more than likely the cement. Ive never been able to do anything for optics that suffer this. Its still useable but doesnt look pretty. If its on the finder its not so bad. This is another reason I dont like cemented optics

[GlenM]

Yep, delamination.

 

Glen.