Pentax SMC-FA 50mm f/1.4 - Review / Lab Test Report
Lens Reviews - Pentax

Review by Klaus Schroiff, published April 2007

Special thanks to Markus Stamm for providing this lens!


It took a while but welcome to the first Pentax lens test here at OpticalLimits. As usual we'll start with a reference lens, typically 50mm primes and the Pentax SMC FA 50mm f/1.4 qualifies here. Despite being one of the most affordable Pentax branded lenses it is also the fastest one in the current Pentax lens lineup. By now it is a fairly old lens and one of the few remaining full format Pentax FA lenses. All Pentax tests will be performed on the K10D - an APS-C DSLR where the FA 50mm has a field-of-view equivalent to 75mm so it behaves like a moderate tele lens within this scope.

The build quality of the lens is very fine based on very good quality plastics and a metal mount. The small rubberized focus ring operates very smooth. As you can see above the lens extends a little bit towards closer focus distances. The front element does not rotate so using a polarizer is no problem. The lens has no internal AF motor and relies on a slotted drive screw operated by the camera. As a result AF operation will generate a moderate degree of noise. The AF speed is very decent on the K10D.

Equiv. focal length75 mm (full format equivalent)
Equiv. aperturef/2.1 (full format equivalent, in terms of depth-of-field)
Optical construction7 elements in 6 groups
Number of aperture blades8?
min. focus distance0.45 m (max. magnification ratio 1:6.7)
Dimensions64 x 46 mm
Weight196 g
Filter size49 mm (non-rotating)
Hoodrectangular (optional)
Other features-