I have never really encountered this problem before.
You can see the extent of the white matter I am seeing on the rear element in the first picture. Next 2 are closer ups with an extension tube set up, pardon handshake, etc, I did a quick one with a tripod only. From what I can discern, it is inside the lens itself, below the surface of the rear element at the back for sure.
So 2 questions:
1) Is it fungus?
2) If it is, would this extent affect IQ?
Thanks a lot in advance, guys.