Today Pentax announced the Pentax K-01 mirrorless system camera: The Pentax K-01 joins the Fuji X-Pro1, Sony NEX, Ricoh GXR, and Samsung NX cameras in the mirrorless APS-C category. Leica is expected to enter this space with their own product, likely later this year at Photokina. The major selling points of the Pentax K-01 are as follows: Natively uses all Pentax K lenses 16MP APS-C sensor featuring the excellent image quality we've come to expect from Pentax DSLRs Sensor-based image stabilization (unlike Sony, Fuji, Ricoh, and Samsung) High quality video Design by Marc Newson In order for the body to natively use Pentax K lenses, the mount to sensor distance is the same as that on Pentax DSLRs and SLRs. Therefore, the body is overall no smaller than that of current Pentax DSLRs, and the ability to adapt lenses from other systems is severely limited. However, one thing I haven't seen discussed anywhere is that the lack of a mirror theoretically allows Pentax to design new lenses which sit deeper into the camera, closer to the sensor, and protrude less from the camera. Imagine a pancake lens which, upon mounting, automatically extends the rear element deep into the camera. Thus, there is the potential for this camera system to be more compact even though the camera body itself is not. Pentax is releasing the camera along with an even thinner version of the Pentax 40mm f/2.8 pancake, which will bear the "XS" designation. In striking contrast to the Fuji X-Pro 1 and Sony NEX-7, the Pentax K-01 offers few tactile controls and no eye-level viewfinder. The design seems to be all about simplicity: One of the most significant questions which has not yet been answered is how effectively the new camera will autofocus existing Pentax autofocus lenses. Unless Pentax has made great strides in contrast-detect AF of their current lenses, this could prove to be a major sticking point for current Pentax DSLR users who might otherwise consider this system. On the other hand, this camera will feature focus peaking, which helps quite a bit with manual focus. I can't help but feel that Pentax missed an opportunity here to be the only APS-C mirrorless system around with both body image stabilization and the ability to adapt a wide variety of lenses. At first glance, I'd say that the Pentax K-01 offers very little aside from design to make it more appealing than a comparably priced Pentax DSLR. Hopefully additional lenses will follow with designs that take advantage of the lack of a mirror. The K-01 will go on sale in March with a price of $750 (US) for body only or $900 for the 40mm lens kit.