Pentax HD 21mm f/3.2 PENTAX-DA AL Limited Autofocus APS-C Lens for K-Mount, Black {49}

Pentax 21mm f/3.2 Limited: the pancake that travels at 31.5mm equiv.

At just 25mm long and 134g, this lens practically disappears on a Pentax body. The pancake form factor isn't a compromise, it's the point. The 21mm focal length gives you a 31.5mm equivalent field of view on APS-C, sitting in that comfortable near-normal wide territory that works across street, travel, and interior shooting without the exaggerated perspective of a true wide. The 68° angle of view gives you enough room to work in tight spaces without distortion becoming a problem.

The HD multi-layer coating does real work here: flare and ghosting control on a lens this small matters, especially when shooting toward light sources or in mixed interior lighting. The SP coating on the front element keeps it clean in practical use, oils and dust wipe off without leaving residue. Seven rounded aperture blades mean out-of-focus areas render smoothly at f/3.2, and the 20cm minimum focus distance lets you get close enough to fill the frame with smaller subjects. Full-time manual focus override means you never have to switch modes mid-shot.

The Limited designation in Pentax's lineup has always meant something specific: machined aluminum construction, optical tuning for character, and a size that fits in a jacket pocket. This lens is a proven example of what that badge represents.

Who It's For

Street photographers working in APS-C Pentax systems get a discreet, pocketable lens that draws no attention and covers a field of view close to what the eye sees naturally. Travel shooters benefit from the 134g weight and 25mm body depth, this adds almost nothing to a pack. Photographers working interiors, whether architectural detail or documentary work in tight spaces, will find the 68° angle of view and 20cm minimum focus distance genuinely useful. Those who shoot in mixed light or against bright sources will appreciate the HD coating's flare control on small-format glass.

Key Features

• 21mm f/3.2 prime with 31.5mm equivalent focal length
• Pancake design at 25mm length and 134g weight
• 68° angle of view for interior and travel shooting
• HD multi-layer coating reduces flare and ghosting
• SP Protect coating on front element repels oil and dust
• Seven rounded aperture blades for smooth bokeh
• 20cm minimum focus distance with 0.17× magnification
• Full-time manual focus override, screw-drive autofocus

FAQ

What's the actual field of view compared to a standard 50mm?

The 21mm gives you 31.5mm equivalent on APS-C, so it's wider than a normal lens but still comfortable for general shooting. You get 68° of view instead of the exaggerated perspective of a true 24mm wide-angle.

Does this lens have autofocus?

Yes, but it uses screw-drive autofocus from the camera body, so speed depends on your Pentax body. Full-time manual focus override means you can grab focus manually without switching modes.

How close can you focus?

20cm (7.87 inches), which is close enough to fill the frame with smaller subjects or work in tight spaces without stepping back.

What's the maximum magnification?

0.17×, so it's not a macro lens, but the close focusing distance combined with the wide field of view gives you flexibility in framing smaller details.

Is there lens stabilization?

No, there's no IS on this lens. For handheld shooting in dim light, you'll rely on the f/3.2 aperture and your camera's native stabilization if it has it.

How does the HD coating affect image quality?

The multi-layer HD coating cuts flare and ghosting, which matters on a small lens where internal reflections can build up. You'll see cleaner contrast and color fidelity, especially when shooting toward light or in mixed lighting.

What size filter thread does it use?

49mm, and the front element has SP Protect coating, so fingerprints and dust wipe off cleanly without leaving residue.