A question on SD cards and recording AVCHD & XAVC,

Should I use one set of SD cards for recording AVCHD [ 32GB ]
and another set of SD cards for recording XAVC [ 64GB ]

And possibly a third set for recording in 4K [ 128 or 256GB ] -

[ currently I have a set of 32GB and 64GB cards. ]

----------------------------------------------------------------------------

Does the 4K update replace XAVC ??

Other than speed requirements imposed by the various codecs (see the table on page 27 of the user guide), I don't think you'd need separate cards.

If picking up the X70, I plan to just get a pair of 256 GB cards (Class 10, UHS-I, SDXC U3).

I don't see any restrictions though in being able to record to the same card with different settings. Though someone with the actual cam in hand would know for sure.

I have not shot in AVCHD, but the cards are formatted to have separate folders for the files from each codec so I would say no problem.