enter image description hereI have a Minolta MC Rokkor-SG 28mm f3.5 that I recently bought. The lens is free from any fungus or haze and event a scratch almost in mint condition. But there is some kind of speck of dust on the external of the front element and it doesn't get off by simply wiping and using any lens cleaner. I also tried using hydrogen peroxide and lighter fluid but still nothing. Then I remember the "lens bubble" which I've read about and is commonly found in older lenses like the one I have. I would like to confirm for those who know much about camera lenses if this is a lens bubble? The spot is on the right side near the Rokkor name enter image description here

  • \$\begingroup\$ What speck? Please highlight it with an arrow, or circle it. \$\endgroup\$
    – scottbb
    Commented Sep 26, 2021 at 16:43

1 Answer 1


I have seen quite some of lens bubbles, but this one does not look like one. It looks like some spot on the coating surface. Try to wipe it with lens cleaning liquid and tissue, if it does not vanish, then most likely coating has some minor damage.


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