The equivalent of a 105mm on a full-frame, very compact (only 26mm long) and very light (only 130g): we go on our first round of reviews of Pentax pancake lenses with the Pentax smc DA 70mm F2.4 Limited (with other reviews to follow later on down the road).

Here Pentax offers a lens with a relatively adequate aperture for taking portraits. We would have liked a slightly larger aperture so as to have a better depth of field for portrait-taking (as a reminder, the greater the aperture and the more shallow the depth of field is what enables photographers to differentiate the subject of their composition from the blur of the background).

This lens has the same high-quality construction as the other 2 pancakes previously analyzed (the Pentax smc DA 21mm F3.2 AL Limited and the Pentax smc DA 15mm F4 ED AL Limited). But we must still ask — is it possible to create such a compact lens without sacrificing image quality?

Measurements

Pentax smc DA 70mm F2.4 Limited mounted on a Pentax K5

The good points of the Pentax smc DA 70mm F2.4 Limited:

  • More than correct sharpness.
  • A bright lens.
  • Well-controlled distortion.
  • Good control of chromatic aberrations.
  • Compact.
  • Light-weight.

The single questionable point about the Pentax smc DA 70mm F2.4 Limited:

  • Vignetting a bit too apparent.

Comparison

Pentax smc DA 70mm F2.4 Limited mounted on a Pentax K5 vs Sigma 70mm F2.8 EX DG Macro Nikon mounted on a Nikon D7000

The advantages of the Pentax smc DA 70mm F2.4 Limited:

  • The brightest (around +0.29EV).
  • The fewest chromatic aberrations.
  • The most compact.
  • The lightest.

The advantages of the Sigma 70mm F2.8 EX DG Macro Nikon:

  • Better resolution.
  • Zero distortion.
  • Better vignetting behavior.

Conclusion

The Pentax smc DA 70mm F2.4 Limited is a beautiful lens — one of the brightest in the Pentax Limited series.

Despite having been unconvinced about the image quality of the first lenses we analyzed in this series, we must say that this 70mm pancake lens turns out to be very interesting for anyone looking for an unobtrusive and light-weight lens. We hope to return to this lens again by comparing it to the Pentax smc FA 77mm F1.8 Limited, which we expect to analyze in the near future.