"Pentax has formally announced the K-01 K-mount mirrorless interchangable lens camera and a revised 40mm F2.8 pancake lens to match. Built around a 16MP APS-C sensor, the camera can mount most of the lenses the company has ever made. It features sensor-shift image stabilization, a 920k dot rear LCD and can shoot at up to 6 frames per second. The rather interesting design is the work of respected product designer Marc Newson and features a logo of his signature on the base of the camera. The K-01 (which the company says should be pronounced 'kay-zero-one'), will cost around $749 body-only and $899 with the 'XS' version of the 40mm lens.
Our biggest concern, based on its dependance on contrast detection autofocus, is the camera's focus speed. Most lenses designed for DSLR-style phase-detection autofocus don't lend themselves to the rapid contrast detection autofocus required by mirrorless cameras. The contrast detection AF on the K-5 works pretty quickly with some lenses but it's not up to the speed of the camera's phase detection focusing, and certainly not a match for the best mirrorless cameras on the market.
And on handling a pre-production version we noticed that, because it features a full depth K-mount, it is a pretty big camera. Below we demonstrate how its size compares to the company's flagship K-5 DSLR."