One reason I prefer Pentax over Canikon

I can't comment on the D300s, but my five-year-old D300 never skips a beat in cold weather. Mind you, it rarely gets below -30C where I live, in recent years, so it's never been tested in real extreme temperatures.

I doubt there are few "semi-pro" cameras made today by any major producer that die when exposed to below freezing temperatures.

I don't know how these misconceptions get started.