Originally Posted by edwliang
thank you all. the little bright dot looks like a hole in coating to me. :-)
Take a magnifier and examine it closely. Could be coating but I'd guess a fleck of dust or possibly the start of fungus. Examine it with loupe and see if it has little branches. If so it's fungus if not probably dust. Lenses often have junk floating around inside. Somehow over time it works itself in or was there from day one. Fungus I'd get it cleaned before the glass is damaged.
You rarely see large bubbles in lenses after the 40's or 50's. In the day bubbles were considered the mark of better lenses. I had a series III Dagor 12" that had a good size bubble which was made in the early 30's or late 20's. Fantastic lens! The glass actually started to oxidize creating a natural coating. I used it for years to shoot Philips Electronics TV catalogs.
I also had a triple convertible B&L Protar VIIA ~12" that had a whopping huge bubbl in the front cell. It was made around 1900 but it performed beautifully.
Bubbles, dust and schneideritis are of no concern but fungus is.