eric_altherr Posted January 30, 2014 Share Posted January 30, 2014 <p>I purchased a Canon 100mm 2.8 macro USM, non-IS lens sight unseen (I know). It has lots of tiny whitish dots in the lens. The center of the lens is clear, and these seems to be evenly dispersed in a ring around the perimeter, but not close to the edge. There is probably 100+ of these specs. Very small, almost look like very small bubbles in the glass, although I do not believe them to be. The appear to be behind the front element. They don't appear to be "fuzzy".<br> They do not show up in any test images, and I am pleased with the image quality - sharp and high contrast. If it never got any worse, I could live with it. I am concerned that if it is organic, it will grow and damage the coatings. <br> I've never seen anything like this, even on decade old FL and FD mount lens I own.<br> Picture of front element showing the dots here:<br> <a href="http://ericryan.smugmug.com/Misc/i-M2JFs2B">http://ericryan.smugmug.com/Misc/i-M2JFs2B</a><br> Anyone seen this before or have ideas?<br> Thanks in advance!</p> Link to comment Share on other sites More sharing options...
phule Posted January 30, 2014 Share Posted January 30, 2014 <p>I would return the lens immediately.</p> Link to comment Share on other sites More sharing options...
JDMvW Posted January 30, 2014 Share Posted January 30, 2014 <p>Could be, even probably is, fungus, I concur with Rob.</p> Link to comment Share on other sites More sharing options...
sarah_fox Posted January 30, 2014 Share Posted January 30, 2014 <p>You might want to pull out a loupe (or a 50mm lens, which will do in a pinch) and get your eyeball up close to the dots for a better look. It might be fungus. It might be a lens coating starting to delaminate from the glass. Maybe a failure of optical cement. Whatever it is, I suspect it's not good. I'd return it too.</p> Link to comment Share on other sites More sharing options...
eric_altherr Posted January 31, 2014 Author Share Posted January 31, 2014 <p>Thanks to everyone for their responses, especially the idea of using a loupe - 50mm lens worked great. They appear to be tiny spots of fungus. The seller agreed to return the lens.</p> Link to comment Share on other sites More sharing options...
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