Pentax SMC-FA 20mm f/2.8 - Review / Test Report
Lens Reviews -
Tuesday, 25 December 2007 18:51
Page 1 of 3
Special thanks to Knut Kampe for providing this lens!
The Pentax SMC-FA 20mm f/2.8, a full format lens, is discontinued by now
but it may be interesting to have a look how it compared to the current
SMC-DA 21mm f/3.2 Limited. When used on APS-C DSLR the
FA 20mm f/2.8 has a field-of-view equivalent to 30mm so it
leaves its original ultra-wide scope towards a mainstream wide-angle.
The build quality of the lens is fine but nothing to rave about either.
Subjectively the plastic quality could be a little better. The small
rubberized focus ring operates very smooth. The lens extends a tiny bit
when focusing towards closer focus distances.
The front element does not rotate so using a polarizer is not a 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 fast on the K10D.
|Equiv. focal length||30 mm (full format equivalent)|
|Equiv. aperture||f/4.2 (full format equivalent, in terms of depth-of-field)|
|Optical construction||10 elements in 9 groups|
|Number of aperture blades||6|
|min. focus distance||0.25m (max. magnification ratio 1:8.3)|
|Filter size||67mm (non-rotating)|