Pentax SMC FA 31mm f/1.8 AL Limited - Lab Test / Review
12 February 2009
Conclusion: The Pentax SMC-FA 31mm f/1.8 AL Limited is an excellent lens. It is already sharp at f/1.8 and razor sharp from f/2.8 to f/11. Distortions and CAs are very well controlled. On the downside it vignettes quite a bit at f/1.8 so the ultra-large max. aperture takes its toll here. The bokeh (out-of-focus blur) is very smooth and buttery which is fairly unusual for a lens with aspherical elements.