Hi there, I'm switching from a full-size DSLR to an OM-D setup, mostly for nature shooting while backpacking. I'm going to get the 12-50 for its weatherproofing and was wondering what other lenses people would suggest. Ideally I would want a cheaper telephoto zoom to extend my range up to at least 300mm and either a wide-angle zoom or prime. My understanding is that there is no shortage of quality primes for the 4/3rds system, but I really don't know anything about telephoto options. Thanks!