I think this will have little relevance to what you want.
It depends on your camera! Chainfire, the "USB expert" who wrote StickMount (enabling external memory stick/cards on the Nexus 7) has an app on the store called DSLR Controller that works with Canon DSLRs and that would be a case of attaching the tablet to a camera ( see photos here [Android 2.3.1/3.x/4.x][27.09.2012] DSLR Controller v0.96.0 BETA [USB HOST REQUIRED] - Page 201 - xda-developers). The app only works with Canon cameras using DryOS but recent Canon compact cameras use DryOS see list here DRYOS - Wikipedia, the free encyclopedia. It may be that they haven't been tested