Pentax SMC DA 18-55mm f/3.5-5.6 AL WR - Lab Test / Review
Lens Reviews -
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Review by Klaus Schroiff, published June 2011
The Pentax SMC DA 18-55mm f/3.5-5.6 AL WR is a fairly unusual "kit" lens. Upon skin-deep inspection of its specifications it just delivers the usual focal-length- and aperture-range like its various counterparts beyond the Pentax world. However, it has a major differentiator marked by the "WR" in the lens name - it is "weather resistant" thus sealed against dust and humidity. This is something usually found in pricey professional grade lenses. From a product perspective it makes sense, of course, because it is primarily sold with the Pentax K-5 which is a weather resistant DSLR. This is certainly smarter than Canon's (EOS 7D) or Nikon's (D7000) approach - they have no weather sealed consumer grade lenses despite weather-sealed APS-C DSLRs. The DA 18-55mm AL WR is also sold separately for about 200EUR/250US$ so it is quite a bit more expensive than "usual" for such a lens. There's also a non-WR version, the Pentax SMC DA 18-55mm f/3.5-5.6 AL II, to supply the budget market.
The build quality of the Pentax lens is clearly above average for a lens in this class. The lens body is made of high quality plastics based on a metal mount. Both the zoom and focus ring have a rubber coating and operate quite smoothly. The focus ring rotates during AF operations which is a somewhat dated behavior but there still need to be some cost-cutting measures and this is in line with other lenses in this class. The lens has a mono-cam extension mechanism which extends/retracts according to the zoom or focus action - the shortest physical length is reached around the 35mm setting. The front element does not rotate though so using a polarizer remains a viable option. Pentax has applied its SP ("super protection") coating to the front element in order to minimize fogging, repel dust and ease cleaning.
The AF relies on the old drive-screw operated by the camera. The AF speed is absolutely fine whereas the AF noise level is a bit on the high side. The AF accuracy of the tested sample was rather mediocre. Quick-shift manual focusing is supported.
|Equiv. focal length||27-82.5 mm (full format equivalent)|
|Equiv. aperture||f/5.3-f/8.4 (full format equivalent, in terms of depth-of-field)|
|Optical construction||11 elements in 8 groups inc. 1x aspherical and 1x SD element|
|Number of aperture blades||6|
|min. focus distance||0.25 m (max. magnification 1:3)|
|Dimensions||68.5 x 67.5 mm|
|Filter size||52 mm (non-rotating)|
|Hood||Petal-shaped lens hood, bayonet mount, supplied, Filter window|
|Other features||weather sealing (6 seals), SP-coating, supports Quick Shift Focus System|