I used to use good quality alkaline AA batteries as well as a 2CR5 lithium block in my RTS III and experienced severe problems in cold conditions: The camera "froze" at 0° Celsius. I sent it to Kyocera Hamburg but they told me everything was OK. Then I bought Energizer lithium AA cells and since then every problem has gone: The camera worked perfect at -15°C and also at +45°C and high humidity and I have filled about 50 rolls with the same set of batteries (they are still going strong). Moreover, they are about 40% lighter than alkalines and rechargeables. (You know, RTS III owners are featherweight freaks ;-)