Pentax Pentax HD PENTAX-D FA 21mm f/2.4ED Limited DC WR Review

The Pentax HD PENTAX-D FA 21mm f/2.4ED Limited DC WR is a bit of a specialist. It's a 21mm prime for full-frame K-mount cameras, and it's built like a tank, landing in the 74th percentile for build quality. At 417g, it's got some heft, and that f/2.4 aperture is a bit of an oddball, sitting in the 65th percentile. It's not the fastest lens out there, but it's clearly built for a specific kind of photographer who values that Pentax Limited series feel.

Where this lens really shines is in its niche. Its macro score is a surprising 68.3 out of 100, putting it in the 76th percentile. That's not typical for a 21mm lens, but with a 1:3.85 max magnification and a 7.1-inch minimum focus distance, it can get closer than you'd think. It also scores decently for portraits and professional work, but its travel score is a low 41.5, which tells you it's not the compact, do-everything walkaround lens.

Performance is a mixed bag, but the highs are high. Optically, it's in the 70th percentile, and the HD coating should help with flare and contrast. The bokeh is rated in the 61st percentile, which is respectable for a wide-angle lens at f/2.4. You're not buying this for shallow depth of field, but it can render backgrounds nicely.

Now, the lows. Autofocus lands in the 47th percentile, so it's just okay, not lightning fast. And there's no stabilization, which puts it in the 39th percentile there. That's a real consideration for handheld shooting, especially in lower light where you can't rely on a super-fast aperture. Versatility is also low at the 39th percentile. This is a tool for specific scenes, not your everyday carry.

The value proposition is tough. At $1547, this is a premium-priced lens. You're paying for the Pentax Limited series build, the unique 21mm focal length on K-mount, and that surprising macro ability. But when you look at the specs—f/2.4 aperture, no stabilization, average AF—it's hard to justify the cost on paper alone. This is a lens for the dedicated Pentax shooter who wants this specific look and feel, not someone shopping purely for performance per dollar.

Compared to the competition, the Pentax 21mm is in a different league price-wise. Take the Viltrox 35mm f/1.7 or the Meike 55mm f/1.8. They're a fraction of the cost, offer faster apertures (f/1.7, f/1.8), and have autofocus. They might not have the same macro chops or tank-like build, but for most photographers, they offer more versatile performance for way less money. Even the Yongnuo 35mm f/1.8 for Sony E provides a faster aperture and AF at a bargain price. The Pentax wins on build and optical pedigree, but it loses badly on price-to-performance and versatility against these modern, value-focused lenses.

Here's the deal. The Pentax HD 21mm f/2.4 is a beautifully built, niche lens with a great macro trick. Its optical and build scores are strong. But the slow-ish aperture, lack of stabilization, and very high price make it a hard sell. I can only recommend it to a very specific person: a Pentax full-frame user who absolutely needs a 21mm prime with character and close-focusing ability, and who doesn't mind the cost. For everyone else, especially those considering other systems, there are more capable and far more affordable options.