I'm unsatisfied of my 80c (chrome lens) in bad light condition (I am completely satisfied in other condition), so few days ago I have bought a used 80CF for a good price. It is in very good shape and the glass seems perfect. But if I look throug the lens toward a bright and diffused source of light I can see that the glass are not completely clean, it seems like tarnished (I don't know if is the exact word; sorry i'm italian), not wery much and don't seems fungus. I wanted compare with my old 80c and I have discovered that also the 80c is affected by this problem (the 80 c is worst). Now my dubt is: Will this problem damage the quality of picture (over all with stong light source in the picture)? The flare and low contrast of the old 80c could depend from this problem of tarnished? Can i have the lens cleaned by a repairman or (if is better) by Zeiss? How much it cost? The T* multicoating could be damaged from this cleaning? Do you thing that is better if I sell the lens and bought another one? I'm not a professional and this is the first time that i write in this forum. Thanks to all for the help.