Here is a nice, concise, review of the Canon 17-120mm servo cine zoom. The reviewer uses it on a Sony F5 but this lens would also work great on a C300 or a C500, with a little rigging. The lens is available in both EF and PL mounts. I recently got a chance to use this lens myself and found it extremely enjoyable to operate.

Canon CN7x17 KAS lens review by SPARKY FILM on Vimeo

Eric Petrie
provideoandtape.com
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