I have a small mark in the centre of my Noctilux lens. It appears to be inside the front lens element and looks like a floating (even though it does not move) dust particle. It does not affect my pictures, but I just wondered if anyone had an idea what it is.

Thanks in advance.

-- enrique munoz (enrique.munoz@ru.pwcglobal.com), June 01, 2001

Answers

It may very well be a dust particle. I've encountered them inside lenses many times where no amnount of thumping and tapping jars them loose so they fall to the sidelines. If the lens is performing well and has no other flaws, a stripdown to retrieve the dust speck would probably be more risk than reward.

-- Jay (infinitydt@aol.com), June 01, 2001.

The typical scenario is that if you ever try to get rid of dust, you get more dust when you are done than when you started. Could be a tiny bubble in the glass as well. I had a an old Contax camera a few years back with an East German Sonnar lens. The lens was full of internal bubbles, had dust also. The images it made were spectacular none the less.

-- Andrew Schank (aschank@flash.net), June 01, 2001.

Last year I bought a used tabbed 50mm Summicron with a tiny speck of something inside the rear element. Experience had already taught me that such defects are inconsequential, so I didn't hesitate to buy it. One would be hard pressed to see the difference in the images.

-- Bob Fleischman (RFXMAIL@prodigy.net), June 02, 2001.