what does a dirty lens or filter lead to?

[Gaurav Aggarwal]

hi everyone,

i was curious what happens if one shoots with a dirty lens/filter?
for example if there are finger prints, smudges, dust, fibers or just fungus
on either the front or the rear element? any personal experiences?

do we get similar marks on the recording media (film/sensor)?
i doubt it. do we get incorrect colors? bad saturation? chromatic
abberations? haze?

thanks,
gaurav