david_klaffenbach

<p>Hi Ellis, I'm fairly certain it starts as a specular highlight off of glasses, an aluminum beer bottle or something else shiny. It's an afternoon shot, so it's sunshine at work. What I'm not sure about is why it isn't a smooth circular pattern (which is what I get if I try to make this happen with out-of-focus streetlamps or such).<br> The lens is old but new to me, and it has more internal dust than any of my other lenses, but I don't think that's the cause of this and the lens appears to be working well in general. It was once a rental lens, so I'm sure it's had its share of photon impact damage (which by the way is a real thing if you're dealing with high intensity lasers - they call it optically induced damage!).</p>

<p>I shot this the other day:<br> <img src="https://i.imgur.com/rJyxhfp.jpg" alt="" width="510" height="339" /><br> I was struck by the appearance of some of the out-of-focus highlights, such as seen in this crop from the upper left corner:<br> <img src="https://i.imgur.com/xGi7Wmf.jpg" alt="" width="462" height="495" /><br> I've since found similar patterns in photos by other folks online (and it happened to be in daytime baseball shots), so I don't think it is due to a lens defect particular to my lens.<br> I'm just curious if anyone knows what the explanation is for this kind of background pattern. The lens is a Tamron 300mm f/2.8, shot at f/4.</p>