The smc PENTAX-DA* 1:4 300mm ED [IF] SDM is a supertele prime lens for Pentax K-mount.

It uses Pentax' silent SDM motor for autofocus on compatible cameras (K10D[1] and K200D upwards), and has Quick Shift Focus to allow manual adjustments in autofocus mode.

Photozone reviewed the lens favourably, stating, "in terms of resolution and contrast the lens is able to produce very good results straight from the max.

Of the ultrasonic autofocus motor, they wrote that it "works like a breeze - it's both fast and almost silent."

"[2] ColorFoto wrote the lens had outstanding sharpness over the entire frame, even wide open,[3] and PopPhoto.com said that "images shot in the field were satisfyingly contrasty and sharp.