When I had the 70-200 f/4 I constantly wished it was a f/2.8, when I upgraded it to the f/2.8 I never wished it wished it was a f/4 so I also agree with Elsa's sentiment.
"Please accept my resignation. I don’t care to belong to any club that will have me as a member" Groucho Marx
Something to keep in mind is that the new AF system from canon (or at least the 5D and 1D's) seems to benefit from f/2.8 lenses (activation/deactivation of cross and double cross type sensors as well as general AF speed)
I've got both at the moment and use them for different scenarios. The 24-105 is the lens that lives on my camera because of its flexibility, weight, size and reach. I have never fiddled with the focus and have to admit that it is a bit softer at F4 but from there on its perfect.
The 24-70 is taken out when I do portraits mmmm and thats about it, it is heavier, bigger , bigger lenshood but sjoe it is sharp from the word go and the 2.8 aperture does its magic.
If I had to choose, cant tell you thats why I have both!
Let me just add - if a lens is not affordable (even after you have sold the the wife and kids) then go with what you can afford. If that is an F4 lens - so be it. But I recon one can sell a wife and kids for enough. so no excuses.
Have kind of made up my mind on the 24-70 2.8 but just not sure if it would be worth going for the expensive MRII. Might have to wait till it is released. Also like the idea of a set of primes but will have to work on that thought a bit more.
I am looking at a second hand Canon 24-70L MK1. Lens is sharp and focus is quick. When I shoot people its sharp and I dont notice Chromatic Aberration (CA). However when I shoot white writing in sunlight the CA is quite evident. How do I know if I have "acceptable" CA or a poor quality lens ? Anyone have samples of "acceptable" CA on a 24-70 at f2.8 and f4
5DMK III, 1DMK4, 550D, S95
Canon 24-70L f2.8, 70-200L MKII f2.8 IS, 70-300L IS f4-5.6, 16-35L f/2.8, 100L f/2.8 IS Macro, 85 f/1.8, 50 f/1.4, Extender 1.4x MKII
Canon 600RT, 580EXII, 320EX
Looking for a nice walk-around lens, and good value for money => go for the 24-105mm (2nd hand R7500-R8500)
It works for me !
(The first reviews on the 24-70 II (F2.8) is fantastic, and I already start saving for it....to be fitted on the 2nd body. I am not selling the 24-105!)
I have been using the 24-105 for more than 4 years and I have never been dissapointed, (except when my aperture blades went after 100,000 actuations), this is an excellent lens, would love the focal range in 2.8 though......
I have both lenses. It is and will remain a difficult choice. A lot depends on what you shoot. If it's events that are mainly indoors (birthdays/parties/weddings) then I would go with the 24-70L. It is sharp and the AF is amazing on the 5Dmk2. It allows the capturing of "fast paced" action of people and expressions that I used to miss on my 24-105L. If your pictures are mainly outdoors and home events the 24-105 is a better lens for this and performs better at f4 than the 24-70L. The 24-70 has more CA than the 24-105 in my own experience. If it were not for my need to capture event photography I would have kept my 24-105L. It is a beautiful quality lens and a better all-rounder.
5DMK III, 1DMK4, 550D, S95
Canon 24-70L f2.8, 70-200L MKII f2.8 IS, 70-300L IS f4-5.6, 16-35L f/2.8, 100L f/2.8 IS Macro, 85 f/1.8, 50 f/1.4, Extender 1.4x MKII
Canon 600RT, 580EXII, 320EX
I have both, and its not an either or for me since they are two totally different lenses - shot live bands with the 24-70 last night where I benefited from the f2.8 - and off-road driving training with the 24-105 today where I utilised the longer reach. If I had to choose 1 though, it would be the 24-105 - its such a versatile and reliable lens.