Thanks for emailing SanDisk Technical Support.
I understand that you want to inquire the compatibility between Panasonic DMC-GF1 and SanDisk Extreme SDHC *** UHS-I *** 16GB Cards.
UHS is the acronym of Ultra High Speed.UHS card is backward compatible with Non-UHS host devices.But UHS card may not achieve the maximum data transfer speeds in Non-UHS host devices.
There,the SanDisk Extreme SDHC *** UHS-I *** 16GB Cards can be used in Panasonic DMC-GF1.However,if Panasonic DMC-GF1 do not support UHS-I,then SanDisk Extreme SDHC *** UHS-I *** 16GB Cards may fail to reach its peak performance in the host device.