Diffraction correction http://www.ricoh-imaging.co.jp/engli.../645z/feature/Pentax will announce a new firmware update for the K-3 DSLR camera in early July that will include a fix for the mirror flutter problem and a new diffraction correction feature that is already available in the new 645z.
The PENTAX 645Z is equipped with full-featured lens correction functionality. Together with distortion and magnification chromatic aberration, peripheral illumination correction and diffraction correction are newly added. Diffraction that occur when stopping down the lens during shooting are effectively corrected on the PENTAX 645Z. Additionally, it is equipped with fringe correction for use in processing RAW images.