I use a Nikon D3100 with an 18-55 and 55-200 lens. Having just made a trip to 3 NPs, I think the multiple lenses are not the best solution. There were a lot of pictures that came out below par, or we totally skipped, because it's such a pain to keep changing lenses. The hardest part is when hiking and you're trying to juggle the body, lenses, and lens covers to take a quick shot and keep moving. If it weren't for the $1k price I'd already have the Nikon 18-300 VR lens. I'm going take a serious look at the Tamron 18-270.