Cheap lens? Diffraction? Dirt?

Started Sep 11, 2012 | Discussions thread
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Crimguy
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Cheap lens? Diffraction? Dirt?
Sep 11, 2012

Background - I was shooting with the 12-50 kit lens with the E-M5. I was adjusting f-stop to determine the aperture needed to create star points on light sources. Below is one of the photos I took:

What is the cause of the granular pattern around the streetlight in this photo? Below is a zoomed-in shot of the light in question:

TIA!
Matt

 Crimguy's gear list:Crimguy's gear list
Canon EOS 5D Olympus OM-D E-M5 Canon EF 50mm f/1.8 II Canon EF 70-300mm f/4.5-5.6 DO IS USM Canon EF 100mm f/2.8 Macro USM +7 more
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