December 28, 2009 - 6:58 am
When you are looking to buy a camera lense for a DSLR and it is speaking about how the lens is, say, 17mm-85mm, what is that saying about the lens? I am unsure and would really like to know. Also, if you could refer me to any good lenses for the canon rebel xs that would be lovely 
Those numbers refer to the focal length and zoom range of your lens. The lower number provides a wider angle of view then roughly when zoomed to about 35mm you are in the area called the normal angle of view, similar to how the eye sees. Then higher than that you are starting to move into the telephoto range bringing things closer to your viewpoint than how the eye sees it.
In regards to other lenses, much of that will depend on what it is you are trying to do with your photography. I am going to assume that your Canon Rebel XS can with a 18-55mm lens, and if that is so then a good possibility is that a telephoto zoom lens would work well. There are zoom that go to 200mm and 300mm, if you want things far away to be as close as possible then the 300mm will get you a closer view then the 200mm.
Below are some link that could be of help. The first, photo.net, is an online community of photographers where you can do some research and gain some more information. Then I listed links for Tamron, Sigma, and Tokina who are independent lens makers that make lens that mount and work on many of the brand name cameras, including Canon. I have owned lenses through the years made by all 3 and the lenses worked very well for me. The last link is to a dealer, I did a search for telephoto zooms that work on Canon so you can see some options and prices.
Hope this helps.
Good luck.
Mark