I will be (hopefully ) purchasing a new lens pretty soon. I want something with a lot of zoom as I am interested in shooting nature and critters apposed to portraiture. I have a Nikon D40 and the 18-55mm lens that came with it. I was taking a look at the Tamron 70-300mm lens, As it is fairly cheap and comes with a lens hood as an extra perk. There is also the Sigma 70-300mm, basically the same price I just don't know whats better, I have heard Tamron and I have heard Sigma. Also If there are any other fairly cheap zoom lens I'm missing please, feel free. Any opinions help, Thanks.