Pentax 12-24mm f/4 ED AL IF SMC P-DA
(From Pentax lens literature) With an Extra-low Dispersion (ED) glass lens element and two aspherical lens elements, the lens offers more true-to-life image reproduction. The image circle in DA-series lenses is designed to perfectly match the 23.5mm x 15.7mm size of the CCD used in Pentax digital SLRs to optimize camera performance. The new design also contributes to a drastic reduction in size, weight and production cost, compared to 35mm-format counterparts with similar specifications.
Metal Pentax KAF Lens Mount
Equivalent focal length to 18.5mm-37mm in the 35mm format with *ist DSLRs
Extra-low Dispersion (ED) glass for superior sharpness and color correction
Responsive "Quick-Shift Focus System" allows instant shift from AF to MF
The image circle is designed to match the CCD used in Pentax digital SLRs
Comes with a lens hood to minimize flare and ghost images.
Pentax 12-24mm f/4 ED AL IF SMC P-DA User Reviews
9 out of 10 points and recommended by Tigger2 (1 reviews)12mm wide angle, constant F/4, good flare control, solid constructionNot fully compatible with camera flash. Minor occasional vignetting.
Manual warns that flash will create lens shadow especially with hood. I notice a slight vignetting at 12mm only occasionally with the hood but otherwise haven't noticed any light drop-off in the corners. Photos are sharp, especially at F/8 through F/16. Moderate CA at F/5.6, minor CA at F/8 limited to lines of very high contrast. Requires circular polarizer - hood has a portal to access filter. Manual focus ring is easy to find. Feels solid in the hand. Dropped 6 feet onto stone and still going strong. Great for landscapes at 12mm and group photos at 24mm. I use this and the 50-200 with my K100D. I don't miss the 25-49 range, but that's me. Highly recommended.reviewed August 1st, 2007 (purchased for $800)