lens hood


Pentax s 200mm f/2.8 fast-aperture prime lens is one of those products that inspire confidence from the outset. This is unsurprising because, being a DA lens, it is intended for demanding users and has been designed to withstand taxing conditions.

On the outside, the lens is fully sealed against dust, dirt and splashes and also benefits from Pentax s SP (Super Protection) coating on the front element to resist contamination by both oily and water-based substances. Inside, it makes use of ED glass to reduce chromatic aberration and is fitted with an SDM (Supersonic Direct-drive Motor) inner-focusing AF system that promises quick and quiet operation.

 lens hood

Being a prime lens there is but a single collar on the barrel, generously sized and ideally located just forward of the middle of the lens. To the rear of the manual-focusing collar are a focused-distance window (with depth-of-field markings for f/22) and an AF/MF selector. Manual adjustments can be applied at any time in AF mode but the resistance offered by the collar is perhaps just a shade too much for comfort.

A generous lens hood is supplied but it is easily dislodged from its storage position, making it a potential liability when handling the lens. More positively, the hood has a  trap door  that can be removed to allow polarising filters to be rotated in situ.

 prime lens

The barrel has a powder-coated texture that makes the lens easy to grip. The flange at the front adds to a feeling of security when picking up the lens and also blends into the hip on the back of the lens hood.

It is interesting to note that on-the-street prices for this lens vary significantly (by approximately ?100) so it could pay potential purchasers to shop around.

 prime lens

Technical testing revealed minor signs of chromatic aberration but a very strong set of MTF results: it is a shame there is a slight drop at f/2.8 but peak performance, between f/5.6 and f/8, approaches an exceptionally impressive 0.4 cycles-per-pixel. Pentax has sensibly limited the minimum aperture to f/22, at which setting the MTF curve only just falls below the critical 0.25 cycles-per-pixel threshold, as the MTF graph on the left shows.

Field testing confirmed the speed and quietness of the AF system and the ease-of-use of the lens in general. Sadly, it was possible to observe colour fringes towards the edges of the frame in some real-world images.

Overall this is a lovely lens that looks and feels very good indeed.

Its performance is generally solid but the presence of chromatic aberration at the extremes of the image field for tricky subjects is a slight cause for concern. Pentax points out that the angle-of-view offered is equivalent to that of a 300mm lens on a full-frame camera and may be trying to align its 200mm f/2.8 with exotic full-frame 300mm f/2.8 lenses but although the angles of view are the same the perspectives will be significantly different. For that reason the lens is best assessed on its own merits, which are many. This is not a cheap lens but it has lots to recommend it. IT

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