I'm pretty new to photography and to start myself off I bought myself a Canon 50D and a Tamron 17-50mm 2.8. Now I'm MOST interested in taking photos of animals- I'm going to be going to Madagascar this December-January for a family holiday so I need to get one or two lenses that can be used to take 'close' (or is it zoom) shots of insects (I was checking out this guys blog and he uses a 100mm 2.8), and 'far away' shots because if there's an animal far off, in a tree perhaps, I want to take that too.
I'm guessing that the 100mm lens is the one to go for? or is there another? And any recommendations for a zoom lens?
PS. I can't afford to spend TOO much money (if I'm not mistaken the 100mm is about 610? Like the Tammy)