Hello, we are looking to buy a new camera. We love taking pictures, (family, vacations, etc.). We currently have a Canon Elph and a Canon Film camera (nice one w/ a Sigma 75-300 lens that we bought for it). Couple of questions, please: is there a big difference in the Canon Xs and the Canon Xsi? We can only see a couple of differences in the description of the two: one has 10.1 megapixels and the other 12.2 megapixels. Is it worth the $80 difference for the 12.2? And, the xsi has a slightly bigger screen (3.0 compared to the xs with its 2.5). Both these cameras says the lens is 18-55. Second question, will our 75-300 lens fit on the Canon Rebel xs or xsi? Thank you very much!