The IS-version is (like the version II with no IS) not a parfocal lens and delivers the ugly 18 rays from small light sources with an aperture of 16, 22 and so on.
umm the 24-70 II has been widely praised for having some of the BEST sunstars around, those rays he diss are a PLUS
Yep, for landscape work, 9 blade apertures is far more better then the 8 found in the 24-105L and 24-70L mkI. As you said, the sunstars are far more attractive and brilliant. None of the 24-70L designs from any marque are parafocal, Canon, Nikon, Tamron, Sigma. So i dont know what this op is ranting about. The 24-70IIL is the sharpest and best lens of it's type ever. Please remmebr that Canon's mkI was the first of it's type from any brand and it lasted for well over 10 years. Nikon have only realease theirs a few years ago, where their 28-70L was the nearest competitor previously. The canon mkII version eclipses all over versions by a noticable margin. The only dissapointments are the price and a little more focal breathing at min focus distance. Thie good news is that the price will come down with time, it's already dropped a lot her in the UK over the last year.