Astronomik CLS filter causing light flare around bright stars. Is this a defect of the filter or am I doing something wrong? (Ignore the tree branches, it was just a test shot.) :
Astronomik CLS Filter
Astronomik CLS Canon EOS Clip Filter - DSLR, Mirrorless & General-Purpose Digital Camera DSO Imaging - Cloudy Nights
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Astronomik Clip-In Filters for Canon EOS - YouTube
Astronomik CLS-CCD XL clip filter, example sub with and without filter - DSLR, Mirrorless & General-Purpose Digital Camera DSO Imaging - Cloudy Nights
Astronomik CLS CCD Canon EOS Clip Filter | High Point Scientific