Hello All I have a Nikon D5000, with a Tamron 70-300 Zoom lense, and its ok. Its not very sharp at 300 MM and thats what I really want. A lense that is gonna give me better results at higher magnification. I'm not a complete photography nut and so I'm not particularly clued up on everything. I've heard that I might be able to get a extender and that will be give me some extra zoom. Can anyone clear this up for me. I'm also have got a Canon Rebel XS Kit, and so I could also look at a lense for that. I mean your the experts so what do you guys think. This is for Sports photography and Wildlife photography, so it needs to be pretty fast so a large aperture. Well if you require more information please do ask! And I thank you in advanced for the help.