Fringing can occur at maximum aperture, where they can be removed at the present time very well by SW or can be used as a design element.
F 1.4 offers ideal opportunities for play with sharpness or blur. At open aperture can be achieved with the lens very "dreamy" designs, very beautiful portrait effects and a magnificent light.
I use the lens to the K-5 and the Kx.
Both the AF is accurate and fast. Dr AF sound is audible, as with all Pentax lenses, which are driven by the internal camera engine to locate near a small battery-operated screwdriver.
The design of the lens optical system is not for everyone. Has something of tuna can.
But in this case, does not count the outside but what remains as a light footprint on the sensor, I can recommend this lens highly enough and would encourage each Penatx photographer her heart.
Just to explain or supplement> One reviewer wrote:
"I have compared with my old Pentax SMC FA 1.4 (manual focus), where it is second to none."
This can not be true, because F and FA are equipped with autofocus and K, M and A lenses not.
