Ok, so I have been playing around with my 18-55mm lens for awhile that my Canon XS came with but I feel really limited with the zooming only getting to 55. I am going to be taking a nature photography class so I am looking into getting a tripod and I want a telephoto lens possibly reaching 200 to 300 zoom I was curious if anyone has some suggestions on the best I can get for under 300? I also plan on picking up the nifty fifty for street shots? Any ideas would be greatly appreciated.