Pentax smc FA 31mm F1.8

Extremely sharp. Excellent build quality. Fast aperture.

Very expensive. Big. Screw-drive autofocus system.

The Pentax SMC FA 31mm f/1.8 Limited is an extremely sharp lens, but it's also extremely expensive.

Not satisfactory image quality near the maximum relative aperture,, Distinct coma already in the corners of the APS-C/DX sensor,, Loud autofocus,, Work against bright light should have been better,, Average price/quality ratio.

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....