These are the best Pentax telephoto lenses when you want long reach, fast and reliable AF, and weather-sealed confidence for wildlife, sports, airshows, and compressed landscapes across APS-C and full-frame K-mount bodies. The HD PENTAX-D FA 150–450mm f/4.5–5.6 ED DC AW is the flagship super-tele zoom—tank-tough sealing, focus limiter and preset buttons for decisive tracking, internal zoom/focus for balance, and crisp optics that pair beautifully with the HD DA 1.4x AW teleconverter for extra pull; it’s the K-1 II/K-3 III go-to for birds and distant field action. For event and sideline work, the HD PENTAX-D FA* 70–200mm f/2.8 ED DC AW brings pro-speed glass, creamy backgrounds, and dependable AF with a robust AW build, while the lighter HD PENTAX-D FA 70–210mm f/4 ED SDM WR offers travel-friendly sharpness, close focus, and full sealing for hikers and hybrid shooters. APS-C users chasing speed and portability should grab the HD PENTAX-DA 55–300mm f/4.5–6.3 PLM WR RE, whose PLM drive is famously quick and quiet, enabling confident AF-C on the K-3 III for birds-in-flight and daylight sports; its retractable build keeps kits small without sacrificing optical punch. Classic primes still shine: the smc/HD PENTAX-DA★ 300mm f/4 ED [IF] SDM (full-frame compatible) delivers prime-level acuity, pleasing bokeh, and works brilliantly with the 1.4x AW converter for 420mm f/5.6 with minimal quality loss, while the smc PENTAX-FA★ 300mm f/4.5 and FA★ 400mm f/5.6 remain cult favorites on the used market for featherweight reach and characterful rendering. Mid-tele coverage with a fast constant aperture arrives via the smc/HD PENTAX-DA★ 50–135mm f/2.8 (APS-C 75–202mm equiv.), a portrait-and-stage staple with Limited-like color and a compact, sealed barrel, and the smc PENTAX-DA★ 60–250mm f/4 offers a longer sealed range with excellent contrast for field sports and wildlife overlays. Budget-friendly tele reach comes from the HD PENTAX-DA 55–300mm f/4–5.8 ED (non-PLM) or the smc PENTAX-DA 50–200mm f/4–5.6 WR, both lightweight choices for hikes and family sidelines in good light. If you favor prime isolation and low-light separation, the HD PENTAX-D FA* 85mm f/1.4 ED SDM AW isn’t long but straddles tele-portrait duties with studio-grade sharpness and a weather-sealed build that survives beach spray and drizzle. Across the lineup, Pentax body strengths multiply tele performance: in-body Shake Reduction steadies framing at 300–450mm and beyond, Pixel Shift unlocks extra micro-detail on static wildlife and distant architecture, the K-3 III’s AF engine and viewfinder make PLM glass track with confidence, and the K-1/K-1 II’s Crop mode turns full-frame teles into “longer” APS-C equivalents without lens swaps. Practical picks: choose the D FA 150–450 AW for the ultimate wildlife/sports zoom, the D FA* 70–200/2.8 when speed and subject separation decide the image, and the D FA 70–210/4 when you want full-frame reach in a lighter, sealed package; on APS-C, run the 55–300 PLM WR RE as the fast, featherweight all-rounder, add the DA★ 300/4 for prime sharpness (with 1.4x AW TC when needed), and use the DA★ 50–135/2.8 for indoor sports, stage, and portrait compression. Field tips: set focus limiters on the 150–450 to cut hunting, use back-button AF with AF-C on the K-3 III for birds-in-flight, keep shutter speeds high (1/2000s+ for fast action), lean on SR for perched subjects and panning, and embrace close-focus at the long end to melt busy backgrounds. Whether you’re tracking kites over dunes, isolating midfield plays through rain, or layering mountains at 300mm, the best Pentax telephoto lenses combine rugged sealing, crisp, color-rich optics, and dependable autofocus—delivering decisive-moment sharpness without hauling giant, unstable rigs.