Actually I have a Takumar with the same paint missing. Any ideas on how to touch up the paint on the lenses?
Nothing like as ugly as the eBay pictures made it out; those must have been *badly* oversharpened from a low-res digital original.

Try Testor's model paint for touch up, applied with a very small brush. It's enamel, so can be applied over lacquer or enamel original paint, flows nicely, the black is *black*, and it's cheap, too.