A wide prime with internal focusing, but is this the best wideangle for K-mount users?
The reason for this difference is due to Pentax’s lens having been designed exclusively for the APS-C format. This can be interpreted either as good news, because the lens is substantially less expensive, or as a drawback on account of its reduced angle-of-view. It is also fitted with a 77mm accessory thread that allows low-profile filters to be fitted to the front of the lens.
Pentax has never been big on extreme wideangle lenses and immediately before the switch to digital the shortest focal length that the company offered for full-frame film use was 20mm. As it happens, that lens gave roughly the same angle-of-view as is now provided by the current 14mm lens for APS-C format cameras.
The 14mm’s reversible lens hood really needs to be deployed before the lens can be used. Once this has been done a flange, which acts as a comfortable hand-stop, is revealed. This comfort is further aided by the 14mm’s internal focusing mechanism, which leaves the focusing ring undisturbed in AF mode yet also allows on-demand manual intervention.
The AF system is quick and accurate but a bit noisy. Manual focusing is a joy thanks to a perfectly located focusing ring and just the right amount of resistance. A focused-distance window is located to the rear and is marked with depth-of-field indications for f/8, f/16 and f/22.
Pentax’s lens is best used at f/5.6 to f/8 but returns good results from f/4 to f/11. Some chromatic aberration was observed in technical testing and there were also signs of slight vignetting when the lens was used wide-open but real-world use produced images that exceeded expectations based on the technical results.