Question about used lens defects

[kellybeard]

<p>I was looking at this one. If you do the 'Enlarge' and look at the 6th & 7th picture you see a ring of white dots around the edge of the glass. What are they, are they normal and do they affect the image quality in any way?<br>

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250745662151&ssPageName=STRK:MEWAX:IT</p>

<p>Anyway, thanks. You guys are a big help to a newbie like me. I'm anxious to get some a tad wider than my sole lens, a 210mm.<br>

Oh, and Merry Christmas!</p>

[craigd]

<p>They look to me like reflections, perhaps from ceiling-mounted track lights. If they were something inside or on the lens, you'd see them in the fifth picture as well. Also, note that the white dots in the seventh picture seem to be in pretty much the same positions in the frame as in the sixth picture, but the lens has been rotated (look for the numbers stamped on the lens mount -- they're near the bottom center of picture #6, but in the lower left corner of #7).</p>

[michael_briggs2]

<p>Lens elements are painted black on the edges to eliminate light reflections. If the paint detaches in spots it causes a defect that looks like bubbles. This is a very minor defect. In principle it might cause an extremely small amount amount of scattered light, thereby reducing contrast, but in practice you will probably not notice any difference in your photos. On the front element, light will scatter forward. On the rear element, light will have to reflect from the film or elsewhere from behind the lens, then from one of these reflective bubbles to reach the film -- which will occur to a very small extent.</p>

<p>It is a bit unusual to see this on a Fuji lens. It is so common on Schneider lenses of a certain age that it has acquired the nickname "Schneideritis"; some of these lenses have much more severe cases then this Fuji lens.</p>

[josh_adams]

<p>just looks like dust and lens flare to me</p>

[sheldonnalos]

<p>+1 on what Michael Briggs said, he's exactly correct.</p>

<p>Generally it's not much of a concern and is not thought to have any effect on image quality. To me the lens looks in good shape overall and would be a nice compliment to a 210mm lens at a good price.</p>

[rodeo_joe1]

<p>Michael nailed it with the "detached" paint diagnosis. Except in most cases like this the paint was never attached in the first place, and therefore it's not really a defect.</p>

<p>I've seen many a brand new lens showing these little bubbles in the edge blackening, and it occurs for the following reason: The edges of lens elements are ground to shape, leaving a coarse textured white finish which needs to be covered and filled with black paint to prevent reflections. Sometimes the thick paint used doesn't quite go right into the ground texture, especially at the join where two elements have been cemented together; hence the perfect ring of little white dots you can see. This degree of "faulty" painting is perfectly acceptable and won't perceptibly affect the image produced by the lens. (But someone really ought to tell lens makers about permanent Magic Marker pens that can blacken ground-glass edges perfectly without leaving little bubbles!)</p>