smc DA 21mm F3.2 AL Limited. The image circle is designed to match the CCD used in PENTAX digital SLRs. Ultra-compact pancake-type design weighs just 4.7 ounces. Exceptional high contrast high resolution optics with minimal aberrations. Responsive ?Quick-Shift Focus System? allows instant shift from AF to MF. Comes with a lens hood to minimize flare and ghost images.