Or you could root the Nexus 7, install Stickmount, and use a USB OTG cable with a USB SD card reader.
EDIT: Of course, if your camera doesn't support MTP, then it probably does show up as a mass storage device, which means you wouldn't need a separate SD card reader and could hook it up directly, though you'd still need your device to be rooted and to use Stickmount.
Sent from my Nexus 7 using Android Central Forums