What is this on my lens?

Don't know what it is, but it appears to be on the inside of the front element. This is a Sigma 15-600 C.
My guess is condensation. But the lens has been kept in a dry place (bedroom). I live near Los Angeles, so humidity is not a problem.
The lens has not been used in 2 years. I took some test photos, and I don't see this showing up.

It appears on the bottom/left side of the element. You can ignore those little white specks, as they are on the outside. I should have brought
my blower/brush with me.

Might be mold.

digital paradise wrote in post #18988095
Might be mold.

If it is mold, I guess it will continue to grow. Looks like sending it back to Sigma is the only thing I can do.

Perfectly Frank wrote in post #18988124
If it is mold, I guess it will continue to grow. Looks like sending it back to Sigma is the only thing I can do.

I’m not an expert on but if it is mold getting on it as soon as possible would probably be the best thing.

It could be a lens fungus although fungus usually looks like tendrils. It might also be water spots from condensation. Either way I would either send it in for a cleaning or remove the front element and clean it DIY.

Thanks. Fungus is the more accurate description when referring to a lens.