I've owned the 17-40 F4L and currently own the 17-55 F2.8IS. The IQ if the 17-40 is very nice -- very "L-like" with excellent contrast and color. It may not be as sharp ultimately as the 17-55 but that only matters if you're making huge prints. My standard product is an 8X10 print and both are more than sharp enough for that.





The 17-55 is a better lens for me for show formals and weddings. At F2.8, you get to use lower ISO. With IS, you get more sharp images in low light. Yes, it's sharper than the L but not by a lot. I've had no dust problems with mine and it's as well-constructed as the L. Both are excellent lenses. If you NEED the extra stop, then there's no question. The 17-55 is well worth the price. If you don't need it, then it's a matter of value and the 17-40 is an excellent value.





Jim