5d MKII's and 7D's are pretty much new technology, and good weather sealing. The D40 is the cheapest DSLR Nikon makes, and i'm sure it's not very weather protected. I'm sure it might be okay with the cold, but if it gets wet, i'm not too sure it would survive. Only one way to find out! It's also all plastic, so if it gets bumped around pretty good, game over.
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2017 Jeep Wrangler JKU
Canon 5D MKIV w/ a bunch of L's |