Lens review

Pentax HD DA 20-40 mm f/2.8-4.0 ED Limited DC WR

8 February 2014
Arkadiusz Olech

11. Summary

  • solid, stylish and sealed casing,
  • good image quality in the frame centre,
  • very good correction of the longitudinal chromatic aberration,
  • no reservations concerning the spherical aberration correction,
  • slight astigmatism,
  • very good work against bright light,
  • moderate vignetting,
  • accurate and relatively quiet autofocus.


  • weak image quality on the edge of the frame near the maximum relative aperture,
  • lateral chromatic aberration at the shortest focal length could have been lower,
  • too slow autofocus,
  • a tad too pronounced coma,
  • average price/quality and price/parameters ratio.

I have no problems whatsoever with understanding the launch of such a lens as the Sigma A 18–35 mm f/1.8. I wouldn’t have such problems also in the case of a 20-40 mm fixed focus f/2.0 model. Still if a producer decides to introduce to the market a 20–40 mm f/2.8–4.0 device, so one with quite average parameters, the only justification of its existence might be the fact that it is also a mechanical and optical pearl, perfectly sharp up from the maximum relative aperture. As our test showed, the Pentax HD DA 20–40 mm f/2.8–4.0 ED Limited DC WR is not such a pearl of a lens so it seems to be aimed only at the biggest fans of that brand, still remembering and venerating the legend of the cult Limited lenses which, currently, is becoming more and more tarnished. New users and those immune to the Limited magic will be hardly encouraged by this instrument to enter the Pentax system.

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Please, understand me well. The Pentax 20-40 mm is not a bad lens. I am sure you can take a lot of great photos with it. However, I am also sure that, with those parameters and at such a price you could and should expect a lot more.