Lack of IS is on this range of focal length may be a good thing. Quality wide angle lenses are hard to design an manufacture compared to telephoto. So if Canon had tried to jam in IS, one of the two will happen - a) sacrifice in image quality. b) heavy monster with even bigger front element and at least costing $2000 more. . . . Logic of 24 and 28 IS primes within the zoom range - If they pulled off stellar IQ wide open with IS, its a win win. Those you don't absolutely need the zoom can have excellent IQ with IS at relatively lower prices, although I agree it would have been better $200 less.
I am a little surprised Canon is not offering IS as a choice, but as a longtime owner of the 24-105 4.0 IS, I have to say I very seldom if ever notice an affirmative effect on image quality attributable to IS. All but the most jittery coffee drinkers can hand hold a wide angle at slow shutter speeds. It simply takes more camera motion to cause a noticeable effect.
I can only detect benefit from IS at about 50mm and up, which means IS would probably be helpful at only about the longest 1/3 of the zoom range on a 24-70. Would that really be worth the extra cost and bulk?
All lenses are a trade off in one way or another. I chose to trade an f-stop for an additional 35mm in zoom range when I went with the 24-105 over the 24-70. This is just the time of year I *LOVE* the 24-105. On the 7D it's a powerful basketball lens, giving me great coverage from 3-point range to right under the basket. The 70-200 is too tight in close and the 24-70 would not have enought reach. (I either use my own monolights or the client's permanently mounted lights, so f/4.0 is not an issue for me.)02_2059.21_58
by Progeny of Light
, on Flickr
The trade off in the new 24 and 28 lenses is less clear to me. As I said, I don't find IS to be terribly useful in wide lenses, and for the money they seem to be asking, even considering these are probably MSRP and not "street" prices, I'd *MUCH* rather have a 28mm 1.8 non-IS for a roughly comparable price, or keep saving money and get a 24mm 1.4L.