HD Pentax-DA 21mm F3.2 Limited

General Image Quality

Sitting between the ultra-wide 15mm Limited and the normal 40mm Limited, the DA 21mm is in many ways a blend of the two. The DA 21mm Limited shows excellent center sharpness at all apertures, with the corners lagging somewhat behind. The corner drop-off isn't as marked as in its wider cousin, but not as impressively consistent as in the 40mm.

Street/Urban Shooting

The DA 21mm Limited, with its 68° angle of view, is in the range often used for street shooting. As such, it is wide enough to show environmental context without the extreme nature of a 15mm or 18mm lens, while still offering some subject isolation like a 28mm or 35mm does.

Street shooting with the 68° angle of view. (Click for larger view.)
K-5 IIs, 1/100s, f/4, ISO 800

The maximum F3.2 aperture is somewhat slow compared to other lenses typically used for street shooting. This will typically mean either longer shutter speeds or higher ISO values, which on modern DSLRs shouldn't provide too much trouble. As discussed in the Construction and Handling page, the DA 21mm Limited's compact size lends to an unobtrusive profile which can be desirable in a street setting.

The DA 21mm Limited has impressively smooth bokeh for a wide angle lens, with little hint of outlining even in high-contrast backgrounds. The rounded aperture blades introduced with the HD version of the lens keeps the background smooth when stopping down.

Like the other HD Limited lenses, the rounded aperture blades do not create the sharp geometric starbursts like the SMC variants. At smaller apertures, the rounded aperture produces a starburst effect, but not as sharply defined as straight blades do.

The DA 21mm Limited does show some chromatic aberration, although it is normally easy to correct in post-processing. The lens has an impressive resistance to flare and ghosting even in extreme scenes.

The lens does show some barrel distortion, visible in some settings. Like with the chromatic aberration, the distortion is easy to correct in post-processing or using the in-camera correction, albeit at the expense of the image edges.

Close Focus

The DA 21mm Limited has excellent close focusing ability, with a minimum focus distance of under 8 inches and maximum magnification of 0.17x. Coupled with its wide 21mm focal length, the lens is capable of dramatic subject isolation for impressive close-ups.

At minimum focus distance, sharp detail and smooth background. (Click for larger.)
K-5 IIs, 1/30s, f/4, ISO 800

Landscape Usage

While not as dramatic as its 15mm cousin, the DA 21mm Limited is a decent landscape lens. Stopping down to F11 produces acceptable sharpness across the frame, with nice color and contrast. Exaggerating the crop, like in the 16:9 example below, helps widen the percieved view.

16:9 crop of a landscape. (Click for larger image.)
K-5 IIs, 1/10s, f/11, ISO 80

The DA 21mm Limited is a best described as a do-it-all lens, from street shooting to close-ups to landscapes. It is acceptably sharp and well-corrected for ghosting and flare, but does show some chromatic aberration and barrel distortion. It's widest aperture is slower than even some zooms, prompting higher ISO or longer shutter speeds in low light, although in many settings is perfectly capable wide open. Finally, its rounded aperture blades maintain its excellent bokeh even while stopped down, at the expense of sharp geometric starburts.