Skip the Speed Booster Math with This Calculator

There is a surprising amount of math in photography and that’s not a subject everyone excels at (I’m looking in the mirror as I type this). Luckily, smart people have made calculating much easier. Enter the the LensMath Speed Booster Effective Aperture Calculator. This handy and free tool gives you the effective aperture (f-number × booster ratio) and full-frame equivalent focal length (focal length × ratio × crop factor) for any lens on a focal reducer. Neat!