... and where are all of those who said "fake!" now?
Guess Sigma are going to bring the ubiquitous 24-105 to Nikon and Sony.
I presume they must be aiming at 24-70 f2.8 II image quality at a price below the 24-70 f4 IS. I don't see how they can match discounted EF 24-105's price let alone the used ones which are out there in their thousands.
The 24-70 f4 IS is a very different lens it would seem. Small and handy, goes well on an ungripped body whereas the Sigma looks like it's a beast.
That will depend on Canon's game plan. Is the 24-70IS a replacement
for the 24-105, or just an additional lens choice? I would expect the Sigma to trounce the 24-105, and handily beat the 24-70 f/4. I doubt it will approach the 24-70II. They will pick that fight with their own 2.8 (or lower) offering. This Sigma will likely be the best single lens solution for folks that don't have the cash or incentive to buy the Tamron or the Canon 24-70 2.8. Naturally, until we see the price, this is all speculation. I would expect it to come in at around $900-1000, but who knows?