Hi guys, I'm deciding to get a film SLR soon, and I realised that there are a number of different batteries to power the different cameras. Some of the most common ones include 2CR5, CR123. Can some of the pros enlighten me regarding the cost of such batteries and more importantly, generally how many rolls can I get out of them. This is to help me determine the total cost of ownership... Also, are there rechargeable ones; would they be most cost effective in the long run?