Pentax SMC P-DA 21mm F3.2 AL Limited

For the moment there's a shortage of info online about the Pentax DA 21mm Limited lens that came out last summer. It's a digital-only design, made to work with Pentax DSLR's like the 100D and 10D, and "Limited" not in the sense of a limited production run but like the three "Limited" lenses Pentax introduced in the late 90's and early noughts to match their new flagship film SLR, which never made it to market.

Those older models were 31/1.8, 43/1.9 and 77/1.8. The DA-based "Limited" series are 21/3.2, 40/2.8 and 70/2.4, all pancakes, equivalent to 31, 60 and 105mm for 35mm format. The oldest man in the world probably couldn't say why Pentax picked those focal lengths, which give their users a pawky wide-angle, a too-long normal or a too-short telephoto, and what Leica used to call a "mountain lens." (I know, they do offer a 14mm DA, which is seriously wide-angle, but it's not "Limited" and it sure ain't a pancake.)

For years now I've been trying to find some digital replacement for my late Contax G2 and its brilliant Zeiss-G lenses. Fed Fuji's Neopan, that kit gave me just what I wanted in B&W look and feel, viz. Diva, this landscape, or the never-popular Dog Run. But film is for young folks; I no longer have the time to fart around with it. My EOS digital kit's fine, but I chose it for Canon's slick, unctuous look, which isn't what I want, or all I want, from black and white. Well...I've always liked Pentax, and believe their best lenses have a special snap, so decided to give them a try.

I began with the 31/1.8 on my wife's Pentax DL and got a happy surprise, as you can see here and elsewhere in my September album. Thus encouraged, I figured I'd build a B&W package using the 31mm as a normal lens. For a portrait-length tele I got the 50/1.4, and found it good. (Examples here and in other photos from 9/27.)

But what about wide angle? After some thought I chose the DA 21mm, taking its quality on faith in the absence of published tests. I wish it were a bit wider, but hey – this is supposed to be a Cartier-Bresson outfit, nothing very long or short.

Well, the 21/3.2 arrived from B&H two days ago. I don't have any bench equipment, but did some field testing to get to know its good and bad points. I'll spare you the intimate details; you can see the results of yesterday's outing to the American Museum of Natural History for yourself. (Caveat: I tweaked the photos in Photoshop just as I normally would, so you can't take the images as unvarnished samples of what the lens captured.) In sum, it's a good lens, with tonal qualities and contrast that please me very much.

It's sharp, yes. Sharpness has become something of a red herring, like megapixel count. It's a necessary but insufficient attribute. Two lenses capable of resolving the same pattern on a chart can be quite different in other ways. I expect a prime lens this well made to be sharp, and wasn't surprised to find it resolving as much detail at f/8 as the 31 or 50, or my Canon 24-105 "L" zoom, and let's leave it at that till somebody puts one of these things on the bench. What I want has to do with luminosity and textures and edges, qualities less easily measured.

So far so good. Two days aren't enough. I'll follow up on this later; for the moment I like what I see and hope I've found a winning combination. What's not to like? Well, f/3.2 isn't great, but it's only a wink away from the usual 21mm aperture of f/2.8, and after all Pentax was trying to keep the lens small – very small. But it's not easy for an SLR to focus a 21mm lens, which is why Leica and Cosina still make rangefinders, so the wider the lens the better. In low light I found that the DL wasn't always getting the focus bang on. Even in good light autofocus seems a bit iffy. Of course the very thing that makes focusing a WA lens hard, its great depth of field, goes a long way toward saving this situation. However, at the museum, where dimness rules, the DL often couldn't find focus at all, and I missed the shot. A decisive-moment combo this isn't.

That may have more to do with the entry-level Pentax body than with the lens. I'll get the 10D when it's available; maybe that camera will have better eyesight. I'll keep you folks advised.

My wife's DL? I kept it and bought her a new 100D, which suits her even better.