On this review photographer Christopher Frost looks at the the Canon EF 11-24mm f/4 USM ultra wide full frame zoom lens.
If you have deep pockets you might be interested in the (reltivly) recent Canon EF 11-24mm f/4 USM – on full frame 11mm is incredibly wide and even on APS-C.
The lens is large and heavy (over 1kg) and has a very large front element (forget about normal filters here). The build quality is excellent. AF is accurate and silent.
Frost tested the lens on both the full frame Canon 6D and the APS-C EOS M3 cameras. Wide open on the 6D at 11mm it is sharp all across (with some CA in the corners), at 16mm the corners are a bit less sharp wide open but stopping down improves the quality quite a bit. At 24mm the center and corners are not as sharp wide open but closing down improves it at about f/8. The lens is considerably better on FF than on APS-C apparently but there is really not a lot of reasons to buy it for APS-C.
As for pricing this lens cost around $2700.