Instructables
video How to Track Down Lens Flares
Lens flares can be an artistic choice instead of an error the same way blood or water splashing onto the lens can be a choice, but if you're shooting in a studio, they're usually just a mistake. If you're shooting a scene with a whole bunch of light sources, it can be tricky to pick out exactly what light is causing a lens flare, so in this Film Lab Quickie shot in an empty (everyone has the flu) studio Mike lets you know how to track 'em down.

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