Yours 70 -200 f4 L IS is a L series lens and should be better than mine which is a not a L sereis lesns. If i can afford, I would like to get hold of the L sereis lens 70 -2 00 f2.8! But that at the moment is beyond my reach.
Camera may also a factor, mine is 40D and yours is perhaps having an older version of CMOS sensor. I am quire happy with 40D CMOS sensor with its ability to record minute details (with a decent lesns of course).
This is a photograph taken about 7 months ago with Canon EOS 400D (that was before I bought the 40D) with its 18(?) - 55 kit lens (a very basic lens without all the frills of USM etc). The result is still quite impressive. The photo was taken at quay side of Newcastle.
