These are the best Pentax lenses for landscape photography when you want edge-to-edge sharpness, disciplined distortion, and weather-ready builds that hike light yet print big—across APS-C and full-frame K-mount bodies—and here’s what to look for as you buy: prioritize filter friendliness (front threads for circular NDs/polarizers vs bulbous fronts that need holders), strong flare resistance and clean sunstars (blade count/shape matters), corner performance at working apertures (f/5.6–f/8), low coma and astigmatism if you also shoot night skies, robust WR/AW sealing, reasonable weight for long approaches, precise manual focus with a distance scale for hyperfocal pulls, and close-focus for foreground texture; bonus points for consistent color across your kit, tripod-collar options on longer zooms, and body features you can leverage like SR, Pixel Shift, and Astrotracer. On full frame, anchor with the HD PENTAX-D FA 15–30mm f/2.8 ED SDM WR for bright ultra-wide coverage, strong corner hold, and tank-tough sealing; pair it with the compact HD PENTAX-D FA 21mm f/2.4 Limited DC WR for jewel-like build, modern coatings, and characterful micro-contrast that flatters environmental scenes. Prime-driven extremes shine with the IRIX 15mm f/2.4 (long throw, low coma, easy filter use), IRIX 11mm f/4 (sweeping horizons, big image circle), and Laowa 12mm f/2.8 Zero-D (tight interiors with minimal distortion); value hunters can add the Samyang 14mm f/2.8 and correct its mustache distortion in post. Mid-range versatility and travel weight come from the HD PENTAX-D FA 24–70mm f/2.8 ED SDM WR for sunrise-to-twilight flexibility and the featherweight HD PENTAX-D FA 28–105mm f/3.5–5.6 ED DC WR for long hikes; compressed layers and ridge abstracts suit the HD PENTAX-D FA 70–210mm f/4 ED SDM WR, while the HD PENTAX-D FA 100mm f/2.8 Macro WR doubles for 1:1 textures between vistas. On APS-C, the HD PENTAX-DA★ 11–18mm f/2.8 ED DC AW is the pro cornerstone—fast, sealed, corner-clean—backed by the smc/HD PENTAX-DA 12–24mm f/4 for rectilinear travel work; tiny Limited primes keep you nimble without losing bite: the HD PENTAX-DA 15mm f/4 Limited (cult sunstars, superb flare control) and HD PENTAX-DA 21mm f/3.2 Limited (pocketable wide context) pair perfectly with the sealed HD PENTAX-DA 20–40mm f/2.8–4 Limited DC WR for a light walk-around. Practical buyer tips: if you love long-exposure water and grads, pick lenses with 67/77/82mm threads or budget for a holder; if blue-hour/astro is part of your workflow, favor f/2–f/2.8 glass with low sagittal smear; for windy ridgelines, lighter WR zooms (28–105 WR, 20–40 Limited WR) beat heavy glass you’ll leave in the car; if you stitch panos, look for low distortion and consistent vignetting for cleaner merges; and if you rely on hyperfocal shooting, choose lenses with firm, repeatable MF rings. Whether you’re threading cathedral atriums, layering tele ridgelines at sunset, or framing the Milky Way above sea stacks, the best Pentax landscape lenses combine rectilinear discipline, smart filter support, and sealed, field-first handling—so you move faster, shoot longer, and bring home big, clean files that grade and print beautifully.