I've used my Nikon FM3a for hours in the cold (<0F). This was using 10 min - hour long exposures, sitting on a tripod for many hours. Sometimes letting the light meter guess the exposure. Usually, just using the bulb feature. Of course, after too much time in the cold, the batteries would fail, so no aperture priority or light meter reading. Otherwise it never missed a beat. I've also used a Nikon FE2 in the cold, but the batteries would eventually fail. I now own three Nikon FM3a's because they are a wonder to use. The FM3a is brilliant.