Originally posted by falconeye I am less decided here. It is true, a new mount makes lenses for other systems available.
But a K mount forces Pentax to commit to make K mount lenses work flawlessly. I consider it a major failure of the industry that they release mirrorless cameras before they coded good enough CDAF algorithms which don't need special lenses with less moveable glass to function in a satisfactory manner.
Pentax lenses (esp. screw drive lenses) have a strong enough motor to work well with CDAF, assuming a good algorithm is used. We should not forget that Pentax PDAF uses a multistep approach to focus too.
Moreover, rumors have it that FA lenses would work, i.e., the K-01 would support screw drive AF. Of course, if it wants to profit from the Ltd. lenses.
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By producing an adapter with the screw drive motor built it you gain all the advantages of K-mount support and gives you the advantages of using other lenses. People who don't own a single Pentax lens could pick-up the body and use it with other lens brands.
Olympus expanded its user base significantly as people who had no Olympus glass bought into M4/3 to use their existing lenses. I have a friend who bought the E-P2 to use with his collection of older lenses. He has now bought an E-P3 and is looking at the new OM-D that is coming out. He has bought the 12mm f/2, 45mm f/1.8, and a Panasonic 25mm. Had he not had the option to use his older glass he never would have picked up the Olympus. There is a larger group of people that will travel this route. I have been waiting on a larger sensor camera like the E-P3 series that gives me this option. Leica, Zeiss, & Voigtlander glass options become available. There are several older Olympus, Contax, Canon, Nikon, & Minolta lenses that are really good that could be come an option.