Yea. You can get great quality from the smaller lenses. But once you get into anything over 100, the Tamrons and Sigma's of the world start to suffer.
I was talking of the 2.8, Im not sure if the F4's had a I and II versions. I know they just released a 70-200 2.8 IS II and its one of the best zoom lenses dpreview has ever shot...but it comes at a price that resembles a downpayment on a nice car.
http://www.bhphotovideo.com/c/product/6 ... 8L_IS.html
4 freaking stops of Image Stabilization and its verified. The MTF graphs were sick.
So yea, I also was looking into the 70-200 F4 because its so cheap...but I also figure I plan on needing a lot of shutter speed. Going from F4 to F2.8 double my speed. So for double the price I get the performance I want. Sure Ill hopefully be in sunlight, but that extra light will come in handy when I need it.
Plus, I can stick a 1.4x converter on it, only loses 1 stop (makes it a F4) and then its effectively a 156-448 F4!!!
Remember, our cameras have the APS-C sensor so all lenses are multiplied by 1.6. so standard 70-200 is actually 112-320.