What Ideal Lens For Basketball Game w/ NEX-7?

I know you don't have one but the SEL50F18 is perfect for this type of situation I shoot Middle and High School Basketball with it and do very well, even the focusing holds up great. And the school lighting is much worst than where you'll be. Just for future reference if you will be doing this on a regular basis. I would take the 40mm also if that's all I had.

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RM