What is it that grows between glass?

[BowerR64]

Ive seen a few lenses that have somthing between the lenses that grows or distorts the glass in a star pattern and i dont understand whats happening. I cant seem to clean it off and it distorts the images and can sometimes cause focus issues.

[kgosden]

It is probably mold or mildew. Don't keep the lenses in a gym locker ;-)

[ReF]

yeah it's probably fungus - common problem

[Rhys]

I have a fungally-afflicted 135mm Tamron. The focussing ring won't quite reach infinity and is a little slack so when I turn it takes a second before it engages. Would I change this lens? Hell, NO. It's one of the sharpest lenses in my collection and the fungus doesn't seem to affect the photos!

[XaiLo]

Try storing the lens and camera with silica gel packs. Silica packs are relatively cheap and they will take care of the moisture problem. Quite a bit of general merchandise are packaged with them.

[Jason25]

Definitely fungus, which is often the kiss of death for lenses :( In the final stages, the chemicals excreted by it will etch the surface of the glass it's on. It takes awhile to get to that point though, usually.