Shooting moving subject (walking) at f/1.8 - poor hit rate in indoor light

It'll still focus on a single selected point for main focus accuracy, but uses the other 9 points to help track movement. In general, I suggest using 9 or 21 for movement depending on how erratic it is, and single only for static shots. I used 9 for the majority of covering an arangetram (indian dance recital the size and importance of a wedding) and had an over 95% keeper rate. I lost only a handful of shots in over two thousand to focusing errors.

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-Eric (17 years old with tons of things I can't wait to learn)
http://eswenson.smugmug.com