In reply to ChrisBrooke:
Hi Chris,
Always scary when you see your name on a UKC forum thread (panic!).
Thanks very much, very kind, I'm glad you like the photos. Yes spot on, for writing the Dolomites guidebook I used the Canon 6d with Canon 17-40, Canon 70-300 and Samyang 14mm 2.8. It was an excellent set up, the 17-40 is a lot of 'bang for your buck' and is also very light for climbing / long walk ins. It takes filters and was my general purpose lens for most circumstances. The 6D is also excellent with really good low light performance. The 'gimmicks' such as wifi and gps were really useful from a guidebook writing perspective as it allowed me to remotely take shots of people climbing whilst belaying them (in conjunction with a smart phone and tripod) and to mark crags accurately on a map.
The Samyang is one of the best night photography lenses for capturing star fields due to it been 14mm and also 2.8 - see article at:
http://www.ukclimbing.com/articles/page.php?id=6741 . Factor in the low cost and the value for money really is amazing.
I switched to Nikon purely on the back of their wide angle lenses (not the body). The Nikon 14-24mm 2.8 is a slight improvement over the Samyang for night shots (a bit sharper and less distortion) and it's also great for climbing photography with it been so wide (the Samyang lacks an auto focus and obviously doesn't zoom). Canon at the time didn't have a wide angle equivalent (the Canon 14mm prime was half again as expensive, provided the same image quality and didn't zoom). Canon have now come out with the 11-24 F4 lens, but it's hellish expensive and like the Nikon 14-24 doesn't take filters.
My current set-up is Nikon D610, Nikon 14-24mm, Nikon 28-300, Nikon 80-400 and a 1.4x teleconverter. I'm looking to upgrade the D610 to a Nikon D810 in the near future, the lens set up is great and covers my personal needs perfectly.
Personally I think there is little difference between Canon and Nikon and I'm not in one camp or the other. Canon build quality seems a tad better, but you seem to get a bit more value for money with Nikon. Swings and roundabouts...
I guess the most important thing is choosing a set up you will actually take photos with. There's no point in having potentially great image quality if you don't take your camera out much as it's a logistical faff. I take my camera everywhere - walking, ski touring, climbing, mountaineering etc - but it's a faff and a lot of additional weight on harder routes. That's why I own the Nikon 28-300 despite having the 80-400 (which is way superior optically), as it's half the size and weight making it a good 'do it all' lens when you don't have a particular shot in mind.
I hope that helps a bit
James