Its Fungi but not a shroom.

Houston we have a problem.
Not showing up at the moment, it might do at f32 but normal f numbers its ok. Old lens and if it fets worse I might have a go and take it to bits.
It only looks like a smudge to my naked eye, was quiet impressed when I took this with the phone.
Houston we have a problem by ta-thanx, on Flickr

Actual footage of Covid there. Yikes.

I can send wetwipes on Prime...

I'll leave it for the time being. Its the putting it back together that was thinking could be the problem.
If not I'll put it on Ebay and sell it has a 70/200 f2.8 paper weight, or door stop.
A shot of it with a camera.
A bit detail by ta-thanx, on Flickr

I've had my moneys worth out of it. I'll keep my eyes open for another.
You can get some good 70/200 f4 Canon L
Will have to wait and see what happens job wise.

Wow
Treat it like a baby and record it's growth into a mature covid

I got a lot on a Nikon lens, I had it cleaned but the man who did it said it could come back.

Ewwww it's patient zero!!!