hi all, can you please tell me what you think of these 2 lenses. the first one is the canon ef 75-300mm /4-5,6/111usm. the price is £80. the second is the canon 70-200 f 4l the price is £375. i have a canon 450d and the 18-55mm lens. i am a complete novice. so i am looking for a few more lenses. hope you can help. kind regards. gboy.