I may be wrong, but I think the FFC is fixed focus.
I tested it in the store where I bought it and it was okay even though the definition was poor, but at home in the evening with low lighting it's pretty much unusable.
IMHO, manufacturers should scrap the back camera in tablets and only put a single, good quality, front-facing one.
HTC Rezound: S-OFF, TWRP 188.8.131.52, ICS Sense 4.1 Pure GSM by Siulmagic on Funky Kernel 3.7 by Snuzzo (testing recent AOSP ROMs all the time).
LG G Pad 8.3 v500: currently 100% stock.