Hey everyone. I jsut signed up for this site, and it looks like thier is a wealth of information here! I have been taking taking photographs with a 35mm slr for a long time, and this christmas i upgraded to a caon digital rebel XTi. I love the camera, and most of my older lenses work on it, including a macro. I have two questions that i am hoping i get many answers on...... 1) How do Sigma, Tamarac, and Quantary lenses rate? I know the differences of elements, groups, fast vs. slow lenses.... what i dont know his how individual brands are???? 2) seeing as how i am now shooting digital w/o a full sized sensor, do people think that a 300mm telephoto will be enough zoom for nature/wildlife photography? Thanks everyone... glad to be a part of this site!