Despite only offering APS-C digital SLRs for the past decade, Pentax has continued to keep the full-frame SMC FA 31mm f/1.8 Limited ($1,099.95) in its catalog. The wide-angle prime lens, which can now be used digitially in all its glory along with the full-frame Pentax K-1, is the definition of a classic. Its all-metal build, premium finish, and character have made it the darling of many a photographer over the years. It's certainly the best 31mm lens ever made—the oddball focal length is part of its charm—and while it has some optical drawbacks that modern lenses sidestep, it remains an excellent option for any Pentax owner, regardless of whether they opt to pair it with a full-frame or APS-C SLR. DesignThe 31mm ($1,096.99 at Amazon) features an all-metal build and is available in your choice of silver or black finish. Older versions of the lens are stamped Made in Japan, but newer ones come off a factory line in Vietnam—you'd be hard-pressed to spot the difference between the tw...
The Pentax SMC FA 31mm f/1.8 Limited has earned legendary status as a stellar wide-angle lens. Despite its age, it's still a strong performer.
Crisp optics, especially when stopped down; All-metal build quality; Wide aperture; Integrated hood; Mechanical aperture control ring; Excellent manual focus experience
Expensive; Dated screw-drive autofocus system; Dim corners and soft edges at wide apertures; Some barrel distortion; Omits weather-sealing