Pentax SMC DA 40mm f/2.8 Limited - Review / Lab Test
Lens Reviews - Pentax
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Review by Klaus Schroiff, published May 2011

Special thanks to Christian Fischer for providing this lens!


Pentax has quite a reputation regarding street photography thanks to their extensive "Limited" lens lineup which covers the range from moderate wide-angles to moderate tele prime lenses. These lenses aren't exactly cheap but ultra compact and high quality items. The Pentax SMC DA 40mm f/2.8 Limited is one of these lenses. Looking at its shape it is quite obvious why it is called a pancake lens - it is as flat. Just like most current Pentax lenses it is a DA lenses with a reduced image circle dedicated to the APS-C format. Its field-of-view is equivalent to 60mm on full format cameras. Now this is a bit of a problem because "60mm" isn't exactly in the sweet spot of user desires. Fortunately Pentax was at least sane enough to keep a relatively moderate price level.

Thanks to the extensive use of metal rather than plastics the build quality of the lens is excellent. The focus control ring of the tiny lens seems to be made for elfs but then there's simply not enough space for anything bigger. The cutey is a bit of weird fellow when mounted on the rather substantial K5 (see above).

Typical for most Pentax lenses the DA 40mm f/2.8 has no internal AF motor and relies on a slotted drive screw operated by the camera. Consequently AF operations generate a moderate degree of noise. The AF speed is very fast on the K5 - finally the focus group is about as light-weight as it gets.

Equiv. focal length60 mm (full format equivalent)
Equiv. aperturef/4.2 (full format equivalent, in terms of depth-of-field)
Optical construction5 elements in 4 groups
Number of aperture blades9
min. focus distance0.4 m (max. magnification ratio 1:7.7)
Dimensions63 x 15 mm
Weight90 g
Filter size49 mm (non-rotating)
Hoodscrew-in type (supplied)
Other features-

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