A useful investment for Pentax K mount my goals on the Fuji X-M1. It allows the use of old lenses of very good quality and cheap mode (M or A) once you set the case. With my 24mm f / 2.8 I now have a perfect 35mm equivalent: no worries of image distortion and the 40mm f / 2 60mm is ideal for portraits. Frankly, it's great!