69 note that the knockoff batteries won’t work in Canon’s charger; they require their own. The first time I plugged in the off-brand charger that came with my generic batteries, it fried itself in 5 minutes (the seller sent me another); YMMV. Finally, off-brand batteries do not work with the Magic Lantern firmware (as of version 0.1.6). More recently, Series 7 SL-E6 batteries have appeared at B&H, which do contain the appropriate computer chip (they aren’t significantly less expensive than the Canon originals, however). You can also purchase a battery grip (for the Canon 5D: BG-E6; for the 7D: BG-E7; for Nikons) for double the battery life, although many still photographers purchase a battery grip for the ergonomic aid it provides while shooting vertically in addition to the extra battery life (you can also use AA batteries with grips). For filmmaking shooting vertically is a moot issue, but considering most support systems require a riser to raise the low-sitting DSLR into a suitable position, the battery grip can also serve such a purpose. Generic battery grips are also available for 1/3 the price of their genuine Canon counterpart (for both Canons and Nikons users report Zeikos makes a quality alternative).
nofilmschool.com/dslr/power