I'm taking an Alaskan cruise in May and have just purchased the D70 with the kit lens. Could someone please suggest some lenses for taking pictures of glaciers from the boat. Also, a lightweight all purpose lens to take on hikes and sightseeing trips. I am new to this forum so I don't know if this next question is too broad or too basic but could someone also talk about shutter speeds and apetures for taking pictures of snow/ice? Thank you.