I'm in the market for a battery grip. Is there an after market grip that I can use that can "harm" the camera. A non Canon grip, would it harm the battery/camera? I asked a local store and they said they would not recommend it and to stick to Canon whether I buy from them or not. I have no knowledge with this item and hopefully I can get some help. I tried finding a used one and no luck. I do have the battery it came with and purchased another Canon battery. Thanks in advanced.