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

On the Pentax K-3 the best corrected wide-angle in our database is the latest HD version of the ultra-compact DA 21mm f3.2 AL Limited. This highly portable ‘pancake’ lens with its high-grade aluminum outer and engraved markings only weighs 4.2 ounces (134g) and measures just 1.0” (25mm) in length. In second place is the now discontinued smc version, which we’re showing for reference. It has the same 11P-Mpix peak sharpness but the HD coatings of the new model have reduced chromatic aberration while also improving uniformity across the field. The small increase in price seems justified, but if you already have the smc version it’s still a great choice.

Pentax HD DA 21mm F3.2 AL Limited 700 18 11
Pentax smc DA 21mm F3.2 AL Limited 650 16 11
Pentax smc DA 12-24mm F4.0 ED AL (IF) 700 15 10
Pentax smc PENTAX DA 14mm F2.8 575 15 8
Pentax smc DA 15mm F4 ED AL Limited 510 14 9
Pentax HD DA 15mm F4 ED AL Limited 700 14 8
Tamron SP 10-24MM F/3.5-4.5 Di II LD Aspherical IF Pentax 499 13 8
Sigma 8-16mm F4.5-5.6 DC HSM Pentax 699 13 8
 

We’ve also included zoom models in the rankings this time, as we’ve still some lenses to add to the sample. From the rankings, it’s clear that the Pentax smc DA 12-24mm f4.0 ED AL while not great on the K-5 is a very good performer on the 24-Mpix K-3 sans AA filter, especially given the relatively accessible price ($700). It’s sharper at the wider end like most zooms of this type and, with a peak sharpness of 10P-Mpix, is comparable in sharpness with the firm’s primes of the same focal length, at least at the wider end.

As an equivalent to a 21mm (on a 35mm FF) the smc DA 14mm f2.8 ED (IF) resides in third place of current models. With a 77mm filter thread and measuring 3.3” (83.5mm) in length it’s a large lens given it was designed specifically for APS-C, but central sharpness is high at f4.0 even if the corners are some way behind. It’s also well corrected for vignetting and distortion, though lateral chromatic aberration is higher than expected.

We also like the 15mm f4 ED Limited for its small size and build quality, though the new HD model’s $700 is quite a jump over its predecessor’s selling price of $510. It has lower distortion and vignetting than the 14mm and it has similar optical performance from f4 onwards, though the corners aren’t quite as sharp at f8-f11.

PentraxK3_WideAngleFieldComparison2

All three primes (21mm, 14mm and the 15mm) perform similarly when stopped down to f5.6. Although the 15mm has a moderate f4 initial aperture, it has the most consistent performance of the three in terms of sharpness at ach aperture. Both the 21mm and the 14mm are a bit soft wide open.