Pentax SMC DA 50 135mm F2 8 ED IF SDM Review | 54 Data compared

The Pentax DA★ 50-135 mm f/2.8 ED [IF] SDM is a versatile APS-C zoom lens that functions similarly to a 75-205mm focal range on a full-frame body, offering a constant f/2.8 maximum aperture throughout its range. Tested on a Pentax K-3II, the lens delivers excellent overall optical quality, producing precise images with highly faithful color reproduction and smooth background transitions thanks to its 9-blade diaphragm. Its manufacturing and finishing are top-tier, featuring high-quality polycarbonate construction and All Weather (AW) tropicalisation that protects against dust, rain, and snow. Mechanically, it benefits from an Internal Focus (IF) system that keeps the lens from extending during use, a 67mm non-rotating filter mount, and a highly practical "Quick Shift" feature for manual focus adjustments. However, it is not fully compatible with full-frame cameras, as it causes severe vignetting that eats into the image even when using a 1:1 crop mode. The review highlights several distinct pros and cons regarding the lens's performance and value. On the positive side, its major strengths include its bright f/2.8 maximum aperture, excellent sharpness (particularly in the center of...

The ePHOTOzine review of the Pentax DA* 50-135mm f/2.8 ED [IF] SDM lens highlights its excellent build quality, weather-resistant construction, and quiet, fast SDM autofocus. It offers a constant f/2.8 aperture with very good center sharpness at maximum aperture, improving to outstanding sharpness between f/5.6 and f/8, all while maintaining internal focusing and zooming for balanced handling. Minor drawbacks noted in the review include somewhat stiff manual focusing, minor uniform distortion, and noticeable chromatic aberration at the frame edges when wide open at f/2.8. While the lens is a costly investment, the review concludes that its premium optical performance and robust construction justify the price.

The PentaxUser review of the smc Pentax-DA* 50-135mm f/2.8 ED [IF] SDM lens highlights a robust, weather-sealed, and premium optic offering excellent edge-to-edge sharpness when stopped down, complemented by a fast f/2.8 aperture and silent SDM autofocus. While praised for its handling and build, the lens shows weaker edge performance at maximum aperture and potential issues with gritty manual focus action in some units.

The PCMag review characterizes the Pentax SMC DA Star 50-135mm f/2.8 ED (IF) SDM as a compact, weather-sealed, and versatile telezoom for APS-C sensors that delivers impressive sharpness across most of its 75-200mm equivalent range. It is praised for its rugged build, fixed f/2.8 aperture, and lighter weight compared to full-frame alternatives, making it an excellent choice for portraiture and event photography. Conversely, the lens exhibits softness at the 135mm end with weak edge resolution, along with noticeable pincushion distortion. Despite the high price tag, it also lacks a dedicated tripod collar.

The Pentax smc DA 50-135mm f/2.8 ED (IF) SDM is a weather- and dust-resistant fixed-aperture zoom lens well-suited for portraiture and mid-range action photography. It features Pentax’s quiet Sonic Drive Motor (SDM) autofocus system, which delivers a responsive performance that proves effective even under very low light conditions. Lab tests revealed strong image quality, with solid MTF curves that consistently peak above the 0.25 cycles-per-pixel threshold across standard apertures. Additionally, chromatic aberration is well-controlled, and the manual-focusing ring can be seamlessly used at any time to override the AF system while remaining static otherwise. On the downside, the lens suffers from specific handling and performance flaws, including a zoom ring that is positioned too far back on the barrel, making physical operation somewhat awkward. Optically, sharpness drops below acceptable thresholds when shooting wide-open at 70mm or using the minimum f/22 aperture across all focal lengths, and testing noted instances of slight underexposure at the shortest focal length. Finally, the lens carries a high price tag relative to its limited sub-3x zoom range, making it a costly investment compared to more...

The ePHOTOzine review highlights the Pentax SMC-DA* 50-135mm f/2.8 ED (IF) SDM as a professional-grade, weather-sealed telephoto zoom for APS-C DSLRs, offering excellent contrast, smooth bokeh, and robust build quality. Its internal focusing and zooming mechanisms provide a durable, non-extending design. While the SDM motor allows for silent autofocus, the review notes the AF speed is relatively slow and edge sharpness at f/2.8 can be soft. Additionally, the lens lacks a physical distance scale, and its premium status comes with a high price point.

The Pentax SMC-DA* 50-135mm f/2.8 ED [IF] SDM lens delivers excellent center resolution and very good border quality at 50mm, even when shot wide-open at f/2.8. Peak sharpness across the entire frame is achieved at f/5.6 for all focal lengths. The lens also controls purple fringing and longitudinal chromatic aberrations quite well during normal real-world use. However, the lens suffers from noticeable optical flaws, including 1.2% barrel distortion at 50mm that shifts to 1.1% pincushion distortion at 135mm. A major drawback is the performance drop at f/2.8 when zooming into 90mm and 135mm, where the image borders suffer and only manage "good" resolution figures. Optical quality and bokeh smoothness deteriorate further at close focus distances, requiring users to stay at least 1.5 metres away at 135mm for optimal results. Additionally, vignetting is quite pronounced at f/2.8 on the longer end of the zoom range. Lateral chromatic aberrations are also prominent at the extreme ends of the zoom range, averaging a width of 1.3 pixels at the image borders.

The PentaxForums review concludes that the SMC Pentax-DA* 50-135mm f/2.8 ED [IF] SDM is a high-performance, weather-sealed zoom lens that offers superior sharpness, particularly at f/5.6, along with excellent wide-open bokeh and low flare. Its compact, lightweight, and robust construction makes it a superior, versatile alternative to consumer-grade lenses. Conversely, the lens suffers from notable distortion and vignetting at the focal extremes, alongside less appealing bokeh when stopped down. Performance is hindered by slow autofocus speeds and a high risk of mechanical failure within the SDM motor, making its high price point difficult to justify compared to modern third-party alternatives.

The Pentax SMC-DA* 50-135mm f/2.8 ED [IF] SDM is a professional-grade, weather-sealed telephoto zoom lens co-developed with Tokina for APS-C format cameras, providing a full-frame equivalent focal range of 75–203mm. Built with high-quality materials, the lens maintains a constant physical length during zooming and focusing, and its non-rotating 67mm front element features a "Super Protect" coating to repel dust, water, and grease. It introduces an ultrasonic "Supersonic Dynamic Motor" (SDM) for near-silent autofocusing, while retaining a legacy mechanical drive screw for older bodies, and supports instant manual focus override via its Quick-Shift system. The review highlights several specific pros and cons regarding the lens's design and real-world performance. On the positive side, it offers robust, weather-sealed construction, a smooth rubberized zoom ring, a relatively light weight of 685g, and an optical design incorporating three extra-low dispersion (ED) elements. On the negative side, Pentax chose not to include a tripod collar, which the reviewer notes as a borderline decision. Additionally, the autofocus speed is not exceptionally fast for an ultrasonic system, and the AF accuracy proved inconsistent, working perfectly when focusing...