When I made the switch this year from APS-C to :43: the major motivating consideration was that I wanted a high quality, light weight set up for taking with me into slot canyons. So far the slots that I have done have been pretty easy, but I want to explore more technical canyons where I will be carrying a lot of gear and will need to keep my camera set up small. My go to lens for slots right now is the Panasonic 7-14mm. I am also very interested in the 9mm prime that Olympus is rumored to be working on. I was hoping that the Olympus EM-10 would be my go to camera, but combined with the Panasonic 7-14 I was getting the purple fringing/blobs in about 90% of my slot shots. It is extremely contrasty in a slot, even when there is no sun anywhere near the little bit of sky I can see. So I bought a used Panasonic GX-7 a few weeks ago to couple with the 7-14mm and have been pretty happy with the results.