Best lenses for Pentax K-3: Recommended wide angle, telephoto and standard lenses

By Kevin Carter - Tuesday January 07 2014

Lens Recommendations
Introduction | Best wide-angle lenses for the Pentax K-3 | Best standard lenses for the Pentax K-3 | Best moderate telephoto lenses for the Pentax K-3 | Best telephoto lenses for the Pentax K-3

Sigma’s new full-frame 35mm f1.4 DG HSM is also available with a Pentax K mount and it comes as little surprise to see it perform well on the Pentax K-3. Even though it’s the best performing model in this category it doesn’t exhibit the quite the same performance as we've witnessed on the Nikon D7100

Sigma 35mm F1.4 DG HSM A Pentax 899 27 16
Pentax smc DA 35mm F2.8 Macro Limited 700 22 13
Pentax HD DA 35mm F2.8 Macro Limited 750 22 13
Pentax smc DA 35mm F2.4 AL 220 22 11
Sigma 17-50mm F2.8 EX DC HSM Pentax 669 21 13
Pentax smc DA 40mm f2.8 XS 250 20 10
Pentax HD DA 40mm F2.8 Limited 550 19 9
Pentax smc PENTAX DA 16-45mm F4 ED AL 335 18 11
Pentax smc DA 40mm F2.8 Limited 360 18 9
Pentax smc PENTAX DA Star 16-50mm F2.8 ED AL (IF) SDM 736 15 10
Tamron SP AF 28-75mm F/2.8 XR Di LD Aspherical [IF] Pentax 499 15 9
Pentax smc PENTAX DA 18-55mm F3.5-5.6 AL II 125 15 7
 

On that camera the Sigma has excellent sharpness across the field at maximum aperture through to f4, with only very slight drop in the corners. And, stopped down to f5.6, sharpness extends right the way to the corners. However, that’s not the case with the Pentax combination. The centers are sharp but the periphery is someway behind. Even at f8 the corners are still very slightly behind, and at f11 diffraction lowers sharpness significantly. In fact, it performs very similarly to the Sony mount version on the SLT-A77 - a camera with an AA filter as well as a semi-silvered (SLT) mirror in the light path. Intriguingly all three cameras have related sensors. Nevertheless, the Sigma is a good performer and it’s competitively priced, given the high-speed f1.4 maximum aperture.

standard-lens-sigma-35mm

Although the highly regarded Sigma 35mm f1.4 DG HSM A performs well on the Pentax K-3, it doesn’t match the performance of the Nikon mount version on the D7100. Curiously, it performs similarly to the Sony model on the SLT

In joint second place in this category are the smc and HD versions of the DA 35mm f2.8 Macro Limited, which isn’t surprising given the reputation. With the same DxOMark score, making it technically joint second, is the modestly priced  $220 smc DA 35mm f2.4 AL. It’s neither a macro (the DA Limited can go to 1:1) or as well made (it doesn’t even have any distance markings, and the build is a little low rent), but it’s a good performer optically. This lens has good uniformity even if it can’t match the sharpness of the DA 35mm f2.8 Macro Limited model till f4. The Sigma may be the sharpest overall, but if you’re unsure about the field of view (it’s one of the most difficult to master) then the Pentax 35mm f2.4 is a good first choice.

All three lenses have something different to offer, but it’s difficult to ignore the Sigma’s high image quality and sharpness levels, stopping down improves uniformity with excellent corner-to-corner sharpness by f8

standard-lenses-measure

Field maps reveal the sharpness (acutance) per aperture setting. The modestly priced smc DA 35mm f2.4 AL has good uniformity but sharpness is a little low till f4.