New Sigma 24-105 f/4 is $899

[Kayaker72]

This was posted earlier, but Canon is advertising that the 24-70 f/4 IS will be available in a kit with the 5DIII starting in November. I haven't seen that this means that the 24-105 will no longer be offered in a kit, but I assume that is just a matter of time.

Sigma is on a bit of a roll with their lenses, but, at least on the surface, this lens doesn't make much sense to me. The Canon 24-105 f/4 is already very good. It could improve a little bit at f/4 and from 70-105. But not much. The 3 stop IS could be improved upon (and honestly, sometimes I think it is more like 2-2.5 stop IS). But I suspect three other things could be going on:

1) This lens is more aimed at non-Canon mounts. From what I've read, the Nikon offering in this range (24-120) isn't that great.
2) Sigma is betting that Canon will stop using the 24-105 as a kit lens which will eventually force it's market price back up to ~$1,100, creating the price differential between the Sigma offering and Canon's.
3) Sigma is betting that Canon will eventually discontinue the 24-105 without replacing it. The bet would be that Canon will stick to the 24-70 and 70-200 ranges.

My guess is that this is a combination of 1 & 2. I actually doubt #3. But, at this point in time, Sigma's entry against Canon doesn't make much sense to me given that the market is flooded with Canon's and the second hand market price is actually lower than Sigma's entry. Of course, perhaps Sigma is about to blow us out of the water with IQ.