>>3463432Fungus isn't as bad as you would think, some of my absolute best and most highly-praised images on /p/ ever were shot on 20 dollar lenses with fungus in them, pic related.
If the fungus is around the outside of the lens elements most of the time you won't have any issues and you can get bargain prices for baller glass because gearfags won't touch them. I snatched up my Nikon 180 2.8 ED for 90 bucks doing that, and it has a huge fucking gouge on the front element too and even shooting into the sun or points of light there are no issues.
If the fungus is thick enough you can get hazing on the element and that does affect image quality. I have a Sigma 135 2.8 with that problem and it's on the front element luckily so I'm going to try my hand at lens repair and see if I can get the front element off to clean it.
Sometimes fungus can damage the coatings on the lenses too, depending on the element and what you are shooting, that can also damage it. But for the most part, light fungus won't be a dealbreaker for image quality even if you pixel peep.
Do make sure though, those fungus lenses are sat out in the sunlight for extended periods of time, I used to do mine all day on the porch. As long as you can kill it with UV radiation it won't spread to other lenses.
tl:dr; no big deal, go shoot your shit.
