The Sigma 18-35mm lens is now at some stores in Canada as I picked mine up at Don's Photo in Edmonton. What a beast of a lens! Build quality seems great but it is a monster. The 1st and 2nd example pics are taken wide open and the 3rd at f3.5. It is great having a constant aperture f1.8 through the whole range. Since it is a fast lens it is a challenge focussing wide open as the DOF is so small. It is also a challenge with the FA 77 ltd.
Pentax may be missing out n the market for fast lenses as that is the trend for Fuji, Olympus and others.
Dale