Yes, all the time. Remove the math nerd stuff, and go out and use them in late season mountainous weather. Not trying to be rude, but do you actually go out and backpack hunt in cold weather? If not, binos are not 70 degrees inside a bino pouch even wearing it on your chest (it’s good for around 10 degree F increase over ambient, btw), in below 20 weather. Not to mention, I don’t, and no one that I know, sleeps with their binos in the bag with them, as they would frost up nearly immediately when pulled out.
You would be hard pressed to name a BRF that I haven’t seen muliple examples used for extended periods of time in that exact scenario. To an extent they all have issues in true cold.
Sigs have been about like most- hit or miss. It seems that Leica's that go back for warranty because of cold issues usually come back working much better. Swarovski EL Ranges have done pretty well, Zeiss’s new ones have done well from the limited time with them. The surprise has been Nikon Laserforce, and Vortex Fury 5000’s. Both have worked flawlessly to well below zero for extended periods. The battery does drain, but if you keep spares close to your body, you’ll get enough life out of them.
Last year on an elk hunt, using two different European “alpha” bino rangefinders I could not get a range at all past 230’ish meters in sub 30 degree weather. No amount of replacing batteries helped. The next morning, even zipping the pouch up under my outer layer I could not range a bull at all. My buddy with a pair of $900 Nikon’s ranged it instantly (666 yards) and I killed it. To be fair, another had Swaro EL Ranges and it worked too.
