Pentax K-1 II has a Pentax KAF lens mount and currently there are 163 native lenses available for this mount.
The latest released lenses that are compatible with the K-1 Mark II are the Pentax FA 50mm F1.4 Classic, the Pentax FA 50mm F1.4 and the HD Pentax-FA 77mm F1.8 Ltd.
K-1 Mark II also has a sensor based image stabilization system that is up to 5.0-stops effective which means that all of these lenses will be stabilized when used on the K-1 Mark II.
Since Pentax K-1 II has a Full frame sensor, it has a focal length multiplier of 1� so lenses will provide their original focal length on K-1 Mark II.
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Pentax K-1 II Lenses with Image Stabilization
Pentax K-1 II Lenses with Weather Sealings