Originally posted by MarkJerling For photos from the helicopter, I figured the K-5 and the DG70-300mm may be a good choice. That camera and lens combination always seem to work well.
I'd reconsider that. My experience is limited to (very) small winged aircraft, but for the supposedly even stronger vibrations in a helicopter, it may be beneficial to work differently than you normally do - don't press the camera to your face to stabilize it, but hold it loosely away to dampen vibrations transferred through your body. The good life view as on the K-1 will help, so would the extra weight. And, more importantly, the K-1 display also provides more maneuvering options for your camera while you are belted to your seat, to get a good view. I like to have my camera strap extended all the way, so I can still have it around my neck to secure the camera when reaching out as far as I can. I suggest to adjust and try that upfront. In the small plane, which my father flies, I can stick the lens through a very small window this way. The K-1 has the same pixel-pitch as the K-5 and no AA filter, so you don't lose anything but gain an option for wider field of view and potentially even a little more detail and marginally better high-ISO handling. One on the ground, you'll for sure have some time to switch your setup for the hike up - by normal standards, the distance and height should be well under 1h (my family does 400m/h on steeper ascents), so there's ample buffer in the estimated 1-1.5h, as there should for the 'not-so-keen' group.
Originally posted by UncleVanya The 35-135 is very noisy focusing if that matters. I'd still make it the primary lens unless you expect it to be heavily frowned on.
That's normally not an issue outdoors, unless the air is dead silent, which it only very rarely is on a mountain top.
Originally posted by MarkJerling So, I'm not planning on carrying too much gear.
What do you use to carry it? I'd strongly recommend a good backpack, it makes a world of a difference compared to a shoulder bag. Even a good shoulder bag with one camera and two lenses bothers me after 20min, but I happily carry my camera backpack with camera, several lenses, clothing, food&water for 2-3 people and a tripod all day.