ed rader wrote in post #2243411
who does landscapes below F4? i own the 17-40L and use it mostly between f5.6 and f11.
as usual too much is made about the extra stop. get the canon.
ed rader
Totally agree, most people wont use a lens past f/4 anyway and if they do, unless they know how to use it the limited DOF will probably ruin the shot 
For low light shooting or for DOF effects even a f/2.8 lens is really too slow, so a fast prime is far better IMO (50 1.4 , 85 1.2 etc.)
As with most things - everyones needs are different, and for some f/4 is not fast enough for them... But even though I don't own the 17-40, the comments I've heard about it are generaly very favourable, it makes a great landscape lens and it can be used on a crop body.