Pentax smc DA 21 mm f/3.2 AL Limited
11. Summary
- small, physically light and solid housing at the same time,
- splendid image quality in the frame centre,
- very fast and accurate autofocus.
Cons:
- significant distortion for such an angle of view,
- noticeable coma,
- very high astigmatism,
- image quality on the edge of the frame near the maximum relative aperture could have been better,
- a bit too high vignetting.
The comparison of pros and cons of the tested lens seems to be not exactly favourable for the Pentax. The problem is that it could be a bit deceiving. The lens had a lot of average results and, for its dimensions, overall it fared quite well. What’s important, the image quality in the frame centre is really high and, combined with a compact, very solid housing, it makes the Pentax 3.2/21 a very pleasant instrument indeed.
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There is another problem, though. Most of standard zoom lenses offer us 21 mm focal length. The purchase of a prime lens makes sense only when it offers something more than a zoom. This “something more” mainly consists of a better fastness or/and higher image quality. Here, unfortunately, such advantages are debatable because a lens like the Sigma 17-70 mm f/2.8-4.0 DC Macro OS HSM at 21 mm is not slower than the Pentax and the quality of images is the same, momentarily even better. What’s more, the Sigma is cheaper. An HSM mechanism and stabilization are perhaps not huge assets in the case of the Pentax system but still it’s better to have them than not. The only advantages provided by the Pentax 3.2/21 are its superior build quality and smaller dimensions. Are these features worth 500 $ you have to pay for this lens? Here I could traditionally answer: everybody should determine it on their own. However, I am going to write something different this time.
It’s good such producers as Pentax, which dare to follow their own path, even if a bit against the tide, exist on the market. There are plenty of classic lenses with classic parameters available on the market and, on that background, the devices of the Pentax Limited series are unique. Even if sometimes it is difficult to find a rational reason of buying them – like in the case of the 3.2/21 model, tested here, which, optically, is bested by the cheaper Sigma 17-70 mm – you don’t always take only purely rational aspects of a purchase into account. I don’t mean here that mythical image vividness which might be important to some users but I certainly don’t fall for it. I rather mean the pure joy of owning something truly original, untypical and made in a less cliché way than most of the equipment available nowadays on the market. I can understand such a feeling perfectly well because in my arsenal of different optical instruments (lenses, binoculars, spotting scopes, telescopes) there are also some gems which, although, not optically perfect, have this “something” which makes them simply a joy to use.
There is also another aspect of this issue. I often happen to complain that the biggest manufacturers have never treated the APS-C sensor seriously. One of the most blatant examples is the lack of a specially dedicated standard EF-S mount lens in the line-up of Canon. A smaller sensor gives us far more possibilities than full frame, after all. You can get smaller, physically lighter devices, very fast and optically good, even on the edges. It’s enough you want to or/and have the possibilities to produce them. Pentax is one of few companies which treats the smaller sensor seriously. Perhaps they don’t produce very fast instruments (and it’s a shame) but we are given something else. Exactly this producer decided, in a very consistent way, to develop a system of small reflex cameras to which you can attach equally small lenses. The Pentax smc DA 21 mm f/3.2 AL Limited fits this policy perfectly well.
Sample shots
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Camera: Pentax K-5 Parameters: 21 mm, f/8.0, exp. 1/200 s, ISO 100 File: JPEG, 4928×3264 pix, 10.75 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/5.6, exp. 1/500 s, ISO 100 File: JPEG, 4928×3264 pix, 11.13 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/3.2, exp. 1/1250 s, ISO 100 File: JPEG, 4928×3264 pix, 9.81 MB |
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Camera: Pentax K-5 Parameters: 21 mm, f/7.1, exp. 1/320 s, ISO 100 File: JPEG, 4928×3264 pix, 10.62 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/4.5, exp. 1/1000 s, ISO 100 File: JPEG, 4928×3264 pix, 10.1 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/9.0, exp. 1/250 s, ISO 100 File: JPEG, 4928×3264 pix, 10.98 MB |
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Camera: Pentax K-5 Parameters: 21 mm, f/4.5, exp. 1/400 s, ISO 100 File: JPEG, 4928×3264 pix, 9.97 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/3.2, exp. 1/500 s, ISO 100 File: JPEG, 4928×3264 pix, 8.49 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/3.2, exp. 1/250 s, ISO 200 File: JPEG, 4928×3264 pix, 8.25 MB |
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Camera: Pentax K-5 Parameters: 21 mm, f/3.2, exp. 1/320 s, ISO 200 File: JPEG, 4928×3264 pix, 9.84 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/3.2, exp. 1/250 s, ISO 200 File: JPEG, 4928×3264 pix, 9.68 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/3.2, exp. 1/1600 s, ISO 100 File: JPEG, 4928×3264 pix, 8.5 MB |
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Camera: Pentax K-5 Parameters: 21 mm, f/4.5, exp. 1/2000 s, ISO 100 File: JPEG, 4928×3264 pix, 8.04 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/5.6, exp. 1/250 s, ISO 100 File: JPEG, 4928×3264 pix, 11.17 MB |
Camera: Pentax K-5 Parameters: 21 mm, f/6.3, exp. 1/500 s, ISO 100 File: JPEG, 4928×3264 pix, 10.31 MB |
