These are the best Pentax fisheye lenses when you want bold, immersive perspective, close-focus drama, and rugged, travel-friendly handling across classic K-mount bodies from APS-C to full frame. The HD PENTAX-DA FISH-EYE 10–17mm f/3.5–4.5 ED is the modern go-to for APS-C: compact, sharp, and coated with HD + SP to tame flare and fingerprints, it focuses incredibly close for CFWA-style foregrounds, delivers a 180° view at the wide end, and, with its hood removed, covers the K-1 in “near-circular” fashion around ~10–11mm for creative full-frame bubbles; it’s also a favorite for underwater housings and de-fish workflows thanks to predictable geometry. Full-frame shooters who want a classic diagonal fisheye should look to the smc PENTAX-FA FISH-EYE 16mm f/2.8, a compact prime with quick manual handling, crisp micro-contrast, and 180° corner-to-corner coverage on the K-1/K-1 II—great for night cityscapes, domed skies, and tight interiors; vintage fans can also score the smc PENTAX 17mm f/4 Fish-Eye (K series) for characterful rendering and robust metal build. If you prefer zoom flexibility on 35mm film or digital full frame, the smc PENTAX-F FISH-EYE 17–28mm f/3.5–4.5 is a cult classic: diagonal at 17mm with that signature curvilinear sweep, then tightening toward a dramatic wide at 28mm while keeping weight low for day-long walking tours. Budget and ultra-wide seekers on APS-C can reach for third-party K-mount options like the Samyang/Rokinon 8mm f/3.5 Fisheye (manual focus but featherweight with punchy contrast) or the Samyang 12mm f/2.8 ED Fisheye (full-frame diagonal that doubles on APS-C with a different look), both offering long, smooth throws that make precise focus pulls easy for video. Creative specialists can add circular-frame fun with legacy circular fisheyes adapted to K-mount, or lean on the DA 10–17’s hood-off trick on full frame for in-camera circles without exotic glass. Across the lineup, Pentax strengths amplify the effect: in-body Shake Reduction steadies handheld night shots at slow shutters, Pixel Shift boosts micro-detail on static scenes, and Astrotracer turns the K-1/K-3 III into a portable star tool—perfect for all-sky Milky Way domes and aurora sweeps. Practical picks: choose the HD DA 10–17 for APS-C one-lens fisheye versatility (and occasional FF bubbles), the FA 16/2.8 for a compact full-frame diagonal with clean edges, the F 17–28 for film-era zoom character on K-1, and Samyang 8/3.5 or 12/2.8 when you want manual-focus value or a different rendering. Shooting tips: get inches from your foreground to enlarge curves, keep horizons centered if you want balanced bend, de-fish selectively in post to mix straight architecture with fisheye energy, and shade the front element—HD/SP coatings help, but sunballs and spray will find that bulb. Whether you’re wrapping cathedral vaults in a single frame, squeezing into tiny music venues, or mapping meteor showers over desert mesas, the best Pentax fisheye lenses pair dramatic geometry with compact, field-proof handling—so your images feel big, dynamic, and unmistakably fisheye.