I am new to this camera and have not received it yet (ordered but can take 4-6 weeks, bummer) but from my reading the online reviews I am finding 2 things...
(Taken from the review at http://www.dcresource.com/reviews/canon/powershot_sx50-review)
1. Sports mode: This scene gets its own spot on the mode dial. The camera will use focus continuously and defaults to burst shooting in this mode.
2. High-speed Burst HQ: the camera takes ten photos in a row at 13 frames/second; do note that the LCD goes black while shooting is in progress, making tracking a moving subject nearly impossible; since the ISO is set to Auto, photos may be noisy.
I also remember reading somewhere that with the HS Burst mode you should make sure to half press the shutter to focus. If you don't then all your pics will be OOF.
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