Pentax SMC DA 40mm F 2 8 XS Lens Review | 54 Data compared

The Pentax DA 40mm f/2.8 XS is an exceptionally slim, lightweight pancake lens designed by Marc Newson, offering a smooth manual focus ring and a non-rotating filter thread, though its ultra-thin design makes it difficult to mount, features a noisy autofocus, and comes with a poorly designed, loose rubber lens cap. Optically, the lens delivers excellent center sharpness wide open at f/2.8, reaching outstanding levels across the frame when stopped down, yet it suffers from limited close-focusing ability and weaker edge performance at wider apertures.

The Pentax SMC DA 40mm f/2.8 XS is an ultra-compact pancake lens designed for Pentax KAF-mount crop-sensor cameras, producing a 60mm effective field of view. Its standout features include an incredibly fast autofocus speed due to its lightweight five-element construction, minimal corner shading, and excellent tolerance against chromatic aberration. Physically, the lens is exceptionally small—half the width of its Limited predecessor—and features a 27mm filter thread with a standard polycarbonate manual focus ring. However, the lens compromises on ultimate optical performance and features to achieve its budget-friendly $250 price point. Optically, it suffers from slight barrel distortion (.25%) and soft corners when shot wide open at f/2.8, requiring users to stop down to f/8 for peak corner sharpness. Furthermore, it lacks a distance scale, does not ship with a lens hood, exhibits a rotating front element during focus, and has a poor maximum magnification of 0.13x that makes it unsuitable for macro photography.

The SMC Pentax-DA 40mm f/2.8 XS is a 9.2mm thick, ultra-thin pancake lens designed with Marc Newson, offering the same optical formula as the 40mm f/2.8 Limited at a lower cost. Users on PentaxForums highlight its excellent central sharpness from f/2.8, vibrant color, high flare resistance, and extreme portability for street photography. Conversely, the design results in notable compromises, including the lack of Quick-Shift manual focus and a missing distance scale. Specific drawbacks include a noisy, screw-driven AF, a very small focus ring, difficult handling when mounting, and an easily lost,, friction-fit lens cap. For full user experiences, visit PentaxForums.com.

The Pentax DA 40mm F2.8 XS is a remarkably small and lightweight pancake lens, serving as an affordable alternative to the Limited version by providing comparable, high-quality image results. It is praised for its exceptional sharpness, strong flare control, and low distortion, offering excellent value for travelers and users of bodies like the Pentax K-01. However, the lens has drawbacks, including an all-plastic exterior with a less premium feel and sometimes finicky handling due to its ultra-compact size. Key downsides include a noisy screw-drive AF system, the lack of a full-time manual focus override, and a loose, easily misplaced lens cap.

The PentaxUser review highlights the SMC Pentax-DA 40mm f/2.8 XS as an exceptionally compact, 9.2mm thick pancake lens that is ideal for portability. It offers excellent center sharpness from f/2.8, a durable metal mount, and smooth manual focusing. However, the review notes the lens has a loud, screw-driven autofocus system, limited close-up performance (0.13x magnification), and less than ideal sharpness at the edges when wide open, requiring stopping down to f/8-f/11 for best results. A key drawback is the non-locking front lens cap, which is prone to falling off.

The Pentax HD DA 40mm f/2.8 Limited is an ultra-compact pancake lens specifically designed for APS-C cameras, highly regarded for its premium aluminum build quality and unique image rendering style. Measuring just 15.4mm in length and weighing a mere 88g, it offers excellent portability alongside a rounded diaphragm and improved coatings over its predecessor. Its standout optical pros include exceptionally low chromatic aberration, highly controlled distortion, and minimal vignetting. Furthermore, while sharpness is only moderate wide-open, central sharpness improves significantly when stopped down just one stop to f/4. However, the lens suffers from notable downsides, including a slightly disappointing overall DxOMark score of 16 points and a low peak sharpness of just 8-Mpix at f/5.6. Like most pancake lenses, it struggles with inconsistent sharpness across the frame and poor corner performance. On the mechanical side, it lacks a built-in autofocus motor, relying instead on a older, nosier screw-drive mechanism driven by the camera body. Additionally, because it offers only a marginal performance upgrade over the earlier smc version, it provides very little incentive for existing owners of the older model...