What are the circles in the sunrise photo of the Roxy Ann skyline that ran with "The Hottest Day" front page story Thursday morning?

-- Corey P., Medford

Photo Editor Bob Pennell's 6:30 a.m. photo shows concentric circles surrounding the sun. This optical effect is referred to as lens flare and often occurs when directly photographing any bright light. Light catching some part of the lens or camera mechanism reflects several times inside the camera and is recorded on the digital sensor in Pennell's camera.

Shading the lens with your hand or a lens hood can reduce or eliminate the effect. In this case the lens imperfection caused something interesting and little unusual to happen: The picture radiates an image of heat — perfect as an illustration for that story. It also happens on film cameras but modern digital camera seem to record the effect a little differently.

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