The specs for JVC's new HC500 camcorder JVC Pro Specifications (http://pro.jvc.com/prof/attributes/specs.jsp?model_id=MDL102557&feature_id=03) indicate the camera only records ProRes in the 4K UHD format. HD (1080p) is recorded in a H.264 format. If this is in fact correct, bummer. I would prefer to be able to record HD also in the ProRes format.

No one has responded to this question, but from a minimum of checking it seems that ProRes is in fact only available in 4K ( and I assume UHD) with this camera... But that's okay, since it's easy enough to edit with and export as 1080.

On a related sidenote... Now that JVC has apparently purchased rights to the ProRes codec, wouldn't it be a nice surprise if it was offered as a firmware update for the LS-300...

The limitation with ProRes is that one needs to record to the SSD -- ProRes won't record to the SD cards, which are limited to H.264.

Recording ProRes in HD (1080p) simply requires setting the System to "HD EXT(SSD)" according to page 57 of the user manual.