28mm M-Rokkor White Spots in Leica and Rangefinders Posted June 21, 2007 Actually, I deal with this problem often and these white spots are from moisture getting under the antireflective paint and causing it to lift, creating an air bubble which appears white. The reason it show up as a spot/dot is because the paint (just as coating) has pores and the moisture can only reach the glass surface via the pore. The paint must be removed and replaced but it is a big job because the front element is machined into this conical mount in the front and a small cemented doublet (next to the aperture) is machined into the rear smaller conical end. Minolta (with this design) created an airspace that is difficult for the moisture to evaporate from. On the other hand condensation can get into almost any space even under the tightest seal. This lens will often also have spots in the coating because of moisture getting thru the coatings pores and that is even more of a problem to repair
28mm M-Rokkor White Spots
in Leica and Rangefinders
Posted
Actually, I deal with this problem often and these white spots are from moisture getting
under the antireflective paint and causing it to lift, creating an air bubble which appears
white. The reason it show up as a spot/dot is because the paint (just as coating) has
pores and the moisture can only reach the glass surface via the pore. The paint must be
removed and replaced but it is a big job because the front element is machined into this
conical mount in the front and a small cemented doublet (next to the aperture) is
machined into the rear smaller conical end. Minolta (with this design) created an airspace
that is difficult for the moisture to evaporate from. On the other hand condensation can
get into almost any space even under the tightest seal. This lens will often also have spots
in the coating because of moisture getting thru the coatings pores and that is even more
of a problem to repair