Why does the a7r2 demand a sdxc class 10 card or uHS1 card, for XAVCS 4K OR XAVCS HD MOVIES? why can a sdhc uhs1 card not work? I have a sdhc UHS-1 class 10 card but it wont work for the video settings SDHC cards offers between 4GB to 32GB and SDXC offers more than 32GB. There is no difference in the quality or security or speed. The transfer speed depends on the "CLASS" of the card mentioned on it and not on whether it is a SDHC card or SDXC.