< Since UV filters don't effect visible light, they don't affect flare caused by a visible light source in the frame.> Any filter, UV, sky, or otherwise introduces two air-to-glass surfaces, either of which can create or amplify flare. Flare is caused by light bouncing off the surface of the glass (hence the benefit of multi-coating which encourages transmission rather than reflectance), not by what kind of glass you have. regards, Henry Posner/B&H Photo-Video http://www.bhphotovideo.com