Sigma France announced K-mount version of its lightweight large aperture zoom lens 50-150mm F2.8 APO DC EX. This lens is specially designed for APS-C digital SLR cameras and consist of 18 elements in 14 groups with 9 diaphragm blades. Minimum focusing distance is 100cm and filter size is 67mm. Dimensions: Diameter 76.3mm X Length 135.1mm (3.0 inches x 5.3 inches), weight: 770g/27.2 oz.
Pentax version of Sigma 50-150mm F2.8 will be available on July 1, 2007 for about $650.
Peter Bernik has tested the Canon version of this lens (100% crops included):
The lens is not as good as one would think when looking at specifications. Sharpness is very good from f4 above, especially towards the long end (100mm and more). CA can be pretty bad at f2.8.