These are the best Pentax lenses with weather-sealing when you want dust/splash protection, reliable autofocus, and color-rich optics that keep shooting through rain, spray, and wind—across APS-C and full-frame K-mount bodies. Full-frame kits anchor with the HD PENTAX-D FA 24–70mm f/2.8 ED SDM WR as the fast mid-range workhorse, the HD PENTAX-D FA* 70–200mm f/2.8 ED DC AW for pro-speed portraits, indoor sports, and stage, and the HD PENTAX-D FA 15–30mm f/2.8 ED SDM WR for ultra-wide landscapes, interiors, and astro; travelers can shave weight with the compact HD PENTAX-D FA 28–105mm f/3.5–5.6 ED DC WR, while hikers who still want reach can grab the HD PENTAX-D FA 70–210mm f/4 ED SDM WR. Wildlife and field action belong to the HD PENTAX-D FA 150–450mm f/4.5–5.6 ED DC AW, whose AW sealing, focus limiter, and customizable buttons tame dust and rain on long days; prime shooters get sealed speed and velvet bokeh from the HD PENTAX-D FA★ 50mm f/1.4 SDM AW and HD PENTAX-D FA★ 85mm f/1.4 SDM AW, and story-rich wide coverage from the weather-sealed HD PENTAX-D FA 21mm f/2.4 Limited DC WR. On APS-C, the HD PENTAX-DA★ 11–18mm f/2.8 ED DC AW is the all-weather ultra-wide cornerstone, the HD PENTAX-DA★ 16–50mm f/2.8 ED PLM AW brings modern optics and lightning-quick PLM AF to the workhorse range, and the HD PENTAX-DA 16–85mm f/3.5–5.6 ED DC WR or tiny HD PENTAX-DA 18–135mm f/3.5–5.6 ED AL [IF] DC WR cover sealed travel days; telephoto APS-C sets shine with the HD PENTAX-DA 55–300mm f/4.5–6.3 PLM WR RE (fast, quiet AF in a featherweight, retractable body) and sealed classics like the smc/HD PENTAX-DA★ 50–135mm f/2.8 ED [IF] SDM and smc PENTAX-DA★ 60–250mm f/4 ED [IF] SDM. Macro and tele primes aren’t left out: the HD PENTAX-D FA 100mm f/2.8 Macro WR is a metal-barrel, WR 1:1 staple for product and nature, and the smc/HD PENTAX-DA★ 300mm f/4 ED [IF] SDM brings sealed prime sharpness for wildlife with graceful teleconverter use. Across the lineup, HD/SP coatings fight flare and water/oil, Quick-Shift MF invites micro-tuning after AF locks, WR/AW gaskets protect in foul weather, and Pentax bodies add in-body Shake Reduction, Pixel Shift for static detail, and Astrotracer for pinpoint stars—so sealed glass goes further. Practical picks: on full frame, run D FA 15–30/2.8 + 24–70/2.8 + D FA* 70–200/2.8 for all-weather event coverage, swap 28–105/3.5–5.6 or 70–210/4 for lighter travel, and add 150–450 AW for wildlife; on APS-C, choose DA★ 11–18/2.8 for ultra-wide storms, DA★ 16–50/2.8 PLM or 16–85 WR for mid-range versatility, 55–300 PLM WR RE for featherweight reach, and 50–135/2.8 or 60–250/4 when subject isolation matters. Field tips: keep a rain cover for the body but trust the seals, use the front SP coat to wipe spray safely, set focus limiters on tele zooms to cut hunting in heavy weather, and lean on SR for slower shutters at dusk—sealed glass plus stabilized bodies mean you come home with sharp, clean files when others packed it in.