These are the best Pentax lenses for nature photography when you want weather-ready durability, crisp micro-contrast, and a kit that covers grand landscapes, wildlife, flora, and distant details—across APS-C and full-frame K-mount bodies—and here’s what to look for as you buy: prioritize WR/AW sealing for rain, spray, and dust; filter friendliness up front (67/77/82mm threads for NDs/polarizers on landscapes); strong flare resistance and sunstars for shooting into backlight; corner performance at f/5.6–f/8 for vistas; a long, precise MF throw and a distance scale for hyperfocal pulls; close-focus capability for foregrounds and textures; fast, quiet AF (PLM/DC/SDM) with focus limiters on tele glass; manageable weight for long hikes; and compatibility with body features you’ll use outdoors like SR, Pixel Shift, and Astrotracer. For full-frame landscapes and environmental scenes, the HD PENTAX-D FA 15–30mm f/2.8 ED SDM WR is the ultra-wide workhorse with strong corner hold and tank-tough sealing, while the compact HD PENTAX-D FA 21mm f/2.4 Limited DC WR adds jewel-like build, modern coatings, and characterful rendering; mid-range coverage comes from the HD PENTAX-D FA 24–70mm f/2.8 ED SDM WR for sunrise-to-twilight versatility or the featherweight HD PENTAX-D FA 28–105mm f/3.5–5.6 ED DC WR for long approaches, and layered ridgelines sing with the HD PENTAX-D FA 70–210mm f/4 ED SDM WR. Wildlife and distant subjects are best served by the HD PENTAX-D FA 150–450mm f/4.5–5.6 ED DC AW—robust sealing, limiter and customizable buttons, internal zoom/focus, and beautiful detail—and it pairs well with the HD DA 1.4x AW teleconverter when reach decides the frame. Macro for flora, fungi, and textures belongs to the HD PENTAX-D FA 100mm f/2.8 Macro WR—true 1:1, rounded blades for smooth falloff, HD/SP coatings for clean speculars—while third-party options expand the toolkit: IRIX 15mm f/2.4 (long throw, low coma, easy filters) and Laowa 12mm f/2.8 Zero-D for rectilinear extremes, plus the Samyang 14mm f/2.8 as a budget ultra-wide for dawn light. On APS-C, the HD PENTAX-DA★ 11–18mm f/2.8 ED DC AW is the pro sealed ultra-wide for storms, dunes, and night skies, the smc/HD PENTAX-DA 12–24mm f/4 remains a rectilinear travel staple, and the HD PENTAX-DA★ 16–50mm f/2.8 ED PLM AW brings modern optics and lightning-fast PLM AF to the core range; tele reach with featherweight speed arrives via the HD PENTAX-DA 55–300mm f/4.5–6.3 PLM WR RE, whose quick, quiet AF-C pairs perfectly with the K-3 III for birds and mammals, while sealed classics like the smc/HD PENTAX-DA★ 50–135mm f/2.8 and smc PENTAX-DA★ 60–250mm f/4 deliver compressed landscapes and wildlife overlays with graceful rendering. Tiny Limited primes keep daypacks light without giving up bite: the HD PENTAX-DA 15mm f/4 Limited (cult sunstars, great flare control), HD PENTAX-DA 21mm f/3.2 Limited (pocketable wide context), and sealed HD PENTAX-DA 20–40mm f/2.8–4 Limited DC WR for walk-around nature storytelling; close-up work on APS-C is handled elegantly by the HD PENTAX-DA 35mm f/2.8 Macro Limited for 1:1 details on leaves, bark, and lichen. Practical buyer tips: if long-exposure water and grads are your thing, choose lenses with common front threads or budget for a holder on bulbous-front ultra-wides; for backlit forests and seascapes, favor HD/SP coatings and blades that produce clean sunstars; hikers should balance reach vs weight—28–105 WR or 20–40 Limited WR often beats heavier glass you’ll leave in the car; if you split time between landscapes and astro, pick f/2–f/2.8 wides with low sagittal coma; for wildlife, look for limiters, customizable buttons, and internal zoom to maintain balance on a monopod; and for macro in the field, prefer internal or short-throw focusing and WR to handle dew. Whether you’re framing misty valleys at dawn, isolating raptors across a canyon, documenting wildflowers at 1:1, or layering tele silhouettes at sunset, the best Pentax lenses for nature photography combine sealed, field-first handling with sharp, color-true optics—so you travel lighter, react faster, and bring home files that grade and print beautifully.