Kit,
I use the 14-24G with Mark's adapter on 1ds3 and still enjoy that great lens.
I posted some crops above comparing the Nikon and the new 17 at 17 at f8-f9 and I was surprised how equal they were to me. I am sure the Nikon is better at wider apertures as the Canon 17 needs about f7.1 to get sharp enough in the corners. Still quite an improvement on their old TS-E 24mk1 like you mention and the 17 is quite an accomplishment for Canon I think.
Canon doesn't recommend using a TC on the 17 in the 17 lens manual but obviously designed it so it could. When using the 17 + TC, the camera still records the focal length as 17 and the lowest f-stop of 3.5 still shows up in the display instead of adding the extra stop.
I use the 14-24G with Mark's adapter on 1ds3 and still enjoy that great lens.
I posted some crops above comparing the Nikon and the new 17 at 17 at f8-f9 and I was surprised how equal they were to me. I am sure the Nikon is better at wider apertures as the Canon 17 needs about f7.1 to get sharp enough in the corners. Still quite an improvement on their old TS-E 24mk1 like you mention and the 17 is quite an accomplishment for Canon I think.
Canon doesn't recommend using a TC on the 17 in the 17 lens manual but obviously designed it so it could. When using the 17 + TC, the camera still records the focal length as 17 and the lowest f-stop of 3.5 still shows up in the display instead of adding the extra stop.