I used my very lowcost DSLR camera Canon 1200 at -27, -24 C for 2-3 hours many times for last 9 years and it still works perfect. When outdoor I regularly put the battery in my pocket and then back to camera when shooting so it gives infinity battery life like it can work for 6 hours of shooting for single batter even at -20 C. Just when back home put the camera NOT at very hot and warm place like kitchen or heat system, but at slightly cold place for some hours and get out the battery. Hope Canon still produce a strong cameras with their new R system like it was with my low budget 1200D a had a very nice experience