I have a Canon Powershot S2 IS. The camera manual recommends use of NiMH rechargeable batteries which I have been using. Recently I found my self in an emergency situation where my batteries went down and I bought Energizer AA lithium batteries. The camera seemed to operate normally. My question is, does it matter which battery type is used as long as they are AA, (1.2 lithium vs 1.5 V NiMH ratings)?