Pentax SMC DA 21mm F 3 2 AL Limited Review | 54 Data compared

The Imaging Resource review highlights the Pentax 21mm f/3.2 Limited SMC P-DA as an ultra-compact "pancake" lens for APS-C bodies, offering a versatile 31mm-equivalent field of view and exceptional, lightweight portability. Its key strengths include superior build quality, a unique compact lens hood design, and impressive sharpness in the center of the frame. Conversely, the lens lacks a physical aperture ring, rendering it incompatible with older film bodies, and its f/3.2 maximum aperture is slower than typical wide-angle primes. Some edge softness and vignetting can occur at wider apertures, though the overall performance remains high for street photography.

The SMC Pentax-DA 21mm f/3.2 AL Limited is a compact, metal-bodied pancake prime for APS-C DSLRs, praised by ePHOTOzine for its robust build quality, excellent handling, and consistent sharpness across the aperture range. While delivering high-quality, lightweight performance, the lens features a 31.5mm equivalent focal length, making it well-suited for street and documentary photography. However, the review notes some optical compromises, including visible barrel distortion and, notably, chromatic aberration when stopped down, alongside a high initial price point. Despite these minor drawbacks, the lens offers impressive, compact performance, making it a valuable addition to a Pentax system, particularly when discounted.

The Opticallimits (formerly Photozone) review highlights the Pentax SMC-DA 21mm f/3.2 AL Limited as a high-quality, ultra-compact "pancake" lens built specifically for APS-C format DSLRs. Delivering a 32mm full-frame equivalent focal length, it stands out as an excellent choice for street photography. Its premium "Limited" status ensures exceptional, all-metal mechanical construction with tight tolerances, a smooth focus ring, and an incredibly lightweight design at just 140 grams. The lens utilizes a camera-driven slotted screw for autofocus, which achieves very rapid speeds due to the light focus group. Additionally, it features Pentax's "Quick-Shift Focus System" for seamless manual overrides and exceptional resistance against backlight flare due to its low number of internal lens elements. However, the review points out several distinct drawbacks inherent to its compact pancake design. Optically, it suffers from a relatively slow maximum aperture of f/3.2, and its peak optical performance is lower than that of larger, conventional lenses. While the center sharpness is exceptionally high straight from the maximum aperture, the border and corner quality lag behind and require stopping down to f/5.6 or f/8 to achieve...

The Pentax smc DA 21 mm f/3.2 AL Limited review by LensTip highlights a highly compact pancake lens tested on a Pentax K-5 camera, evaluating its ultimate balance of portability and optical performance. The primary pros of this lens include its small, physically light, yet structurally solid housing design, paired with a very fast and accurate autofocus mechanism. Optically, it delivers splendid image quality in the frame center, exceeding 40 lpmm at the maximum f/3.2 aperture, rising to 46 lpmm at f/4.0, and peaking near 51 lpmm at f/5.6. LensTip.com However, its ultra-compact form factor forces significant optical compromises that make up the review's primary cons. The LensTip review notes that the edge of the frame suffers near the maximum aperture, rendering border images not fully useful due to high initial astigmatism and noticeable coma. Additionally, the lens struggles with significant distortion for its field of view and suffers from a bit too much vignetting. While stopping down the aperture by 1 EV effectively eliminates the fuzzy edge performance and resolves the astigmatism, LensTip concludes that the extensive list of...

The OpticalLimits review concludes that the Pentax SMC DA 21mm f/3.2 AL Limited is a very high-quality pancake lens that serves as an excellent, unobtrusive option for street photography due to its 32mm full-frame equivalent field of view. Built as part of Pentax’s prestigious Limited series, it features a rugged, all-metal construction with tight tolerances and a smooth, slightly damped manual focus ring. Key performance pros include an exceptionally high center sharpness straight from its maximum aperture, excellent handling of backlighting and flare due to its low element count, a non-rotating front element for easy polarizer use, and very fast autofocus speeds enabled by its lightweight optical group. It also features a "Quick-Shift Focus System" that allows for instant manual focus overrides once the autofocus locks. However, the pancake design forces several optical and physical compromises that serve as the lens's main cons. It offers a relatively slow maximum aperture of f/3.2, and its peak optical performance is lower than traditional primes because the compact chassis restricts the number of corrective lens elements. While center sharpness is superb, edge and...

The DXOMARK testing overview for the Pentax smc DA 21mm F3.2 AL Limited lens evaluates its optical performance on APS-C sensor camera bodies like the Pentax K-5 IIs. Released in February 2006, this pancake prime lens receives an overall DXOMARK score of 15 points, achieving its optimal performance when stopped down to an aperture of f/5.6. The lab metrics highlight a peak sharpness score of 10 P-Mpix, alongside a transmission rating of 3.4 TStop, illustrating the slight light loss common in ultra-compact lens designs. The primary pros revealed in the laboratory metrics are its exceptionally well-controlled distortion, which measures at a minimal 0.6%, and a fast autofocus capabilities aided by its tiny, lightweight footprint. On the downside, the notable cons consist of prominent vignetting reaching -1.2 EV when shooting wide open and a high chromatic aberration measurement of 17 µm, which can cause noticeable color fringing near the frame edges. Additionally, while the center resolution remains highly commendable, the lens exhibits a drop in peripheral sharpness that is only fully remedied by closing the aperture down to f/5.6.

The SMC Pentax-DA 21mm F3.2 Limited is a highly portable, all-metal "pancake" lens for APS-C DSLRs that offers a 31.5mm equivalent view with rapid, precise autofocus and excellent 20cm close-focusing capabilities. Users praise its compact, 140-gram design, robust build, and ability to deliver vibrant, high-contrast imagery, making it an ideal choice for street and travel photography. Conversely, the lens has a modest f/3.2 maximum aperture, which restricts low-light performance and can lead to corner softness when wide open. Reviewers note that optimal edge-to-edge sharpness requires stopping down, and report issues with barrel distortion and a restrictive lens hood design.