Originally posted by Pål Jensen The Nikon D400 at $1800 is rumored for September. It was delayed due to the flooding in one of Nikon factories (cheaper APS bodies got priority) according to rumors. The Canon 7D MkII is also on the horizon. Canon have said that they will make more APS lenses and I would not be surprised of they make fast and professional ones. To distinguish APS from 35mm you can either make small and light lenses something Pentax have done to a large extent, or make faster lenses cheaper something Sigma has done with this one. I suspect more will follow the example.
The other rumour is that it as delayed because it was too close in spec to the 7200, where the real difference is the frame buffer.
I think Canikon are taking a big pause on any new APS-C until they see where demand is headed and at what price points. Their FF prosumer products are eating away at their higher-end APS-C, so any D400 or Canon equivalent is not going to have anywhere near the sales of a previous models, not in a stagnant market.
The problem for the Sigma lens isn't its price or its aperture. It's the size of the thing. It's a pushing 1kg on camera bodies 2/3 the mass. Followed by the very limiting FL zoom range. That's probably the real reason no OEM has made such a lens when the consumer thrust has been away from big glass in APS-C (but willing to buy it on FF). Far better for Canikon to aim their big glass customers to FF (and more DOF play to boot). This Sigma lens takes away any APS-C advantage in body size. Again, why only Sigma could make this lens.
Apparently Canon's SL1 has been selling gangbusters and it goes in the opposite direction from such big glass. EOS-M has flopped (they will re-design a rebound...and it's also designed to replace Canon's handy cam video market), so we'll have to see if the race for smaller DSLR's is on to combat sales lost to mirrorless.
And that's where Pentax shines. Smaller bodies, small glass. OVF retained in a DSLR. I'm not saying the Sigma's not great, just big and limiting and going upstream in market where the downstream waters are getting faster.
I hope Pentax is designing the tiniest DSLR ever because, frankly, the K-30 looks a bit silly with a DA40 and barely non-comical with a DA21. I saw an SL1 with a Canon pancake and it looked...normal, and infinitely more holdable than the Sony NEX it was positioned next to. In fact, the SL1 compared in size favourably with the 2x more expensive Olympus OM-D which frankly requires its grip to be useful (and markings on the inscrutable controls...I cannot figure that camera out, but it's beautiful). I would buy a non-WR K-30/50 that was 20% smaller as a second camera paired with the Ltd's and never, ever, ever, look at another mirrorless again (unless it is a deeply discounted RX-1). Keep the K-30 for APS-C "big glass", nit right now the Pentax bodies don't really line up with their flagship prime glass.
Anyway, these new forms of camera are really not amendable to such big glass as the Sigma. It's kind of like an elephant rising a horse.