In reply to buffalo606:
If you want a climber and enough background to give a sense of scale you need to go wide (15mm or wider on m43). The wider the lens the closer you need to be to your climber though. I personally use a samyang 7.5 fisheye, but that's really too wide - it's often difficult to get close enough to the climber, and some people don't like the distortion. I think all the other m43 wides (panny 7-14, oly 7-14, 9-18, oly 12 & 12-40) have good reputations, so it's just down to cost and AoV required.
Post edited at 21:10