Best lenses for your Pentax K-50: Pentax lens overview

Introduction

At $699 body only, the K-50 replaces last year’s unconventionally styled K-30 but besides the return to a more familiar body design and many similar features such as six frames per-second continuous shooting and a top shutter speed of 1/6000th sec it adds an upgraded image processor and doubles sensor sensitivity of the K-30 to ISO 51,200. It’s a very likable camera and as we’ve shown in our past report, the K-50 is an excellent performer, achieving a DxOMark Sensor score of 79 points overall; just ahead the firm’s APS-C Ricoh GR, and only a couple of points behind the top-of-the-range Pentax K-5 II models. Our DxOMark lens scores take into account the sensor performance of the camera, especially the results from the Color Depth test and Dynamic range. Noise also affects the testing as one of the many criteria of the lens scores is based on the sharpness in low light levels (see here).

Database Overview

We’ve tested the K-50 with 28 lens models, ranging in focal length from 10mm (equivalent to 15mm in full-frame 35mm angle of view) with the Tamron SP 10-24mm f/3.5-4.5 Di II LD Aspherical IF up to 300mm (450mm equivalent) using the premium Pentax smc DA Star 300mm F4 ED (IF) SDM lens.

Admittedly, one or two lenses are full-frame types such as the new Sigma 35mm f/1.4 Art-series and older Tamron SP AF 28-75mm f/2.8 XR (42-113mm equivalent) model, but the majority are APS-C types made by Pentax. While it’s debatable whether models like that are wholly suitable for APS-C cameras the lenses are available in Pentax mount and, therefore, entirely reasonable to compare the optical performance.

Please note that we’ve not yet had the opportunity to analyze the Pentax 31mm f/1.8, 43mm f/1.9, 77mm f/1.8 Limited models or the 18-135mm f/3.5-5.6 and 60-250mm f/4.0 zooms, however we will be publishing the data on these important models in the future and will update the findings of this overview.”

For more information about the sensor check our Pentax K-50 sensor review

As we’ve seen with other makes the Sigma 35mm f/1.4 DG HSM A is the best performing lens of its type and of the 28 lenses models that we’ve analyzed on the Pentax K-50. As the equivalent to a 50 mm or thereabouts it’s a large and heavy lens but the image quality is terrific. Note that we’ve not yet assessed the Pentax 31mm f/1.8, 43mm f/1.9 or the 77mm f/1.8 Limited models.


 

Sigma 35mm F1.4 DG HSM A Pentax 899 24
Pentax smc DA Star 55mm F1.4 SDM 640 23
Pentax smc DA 50mm f1.8 249 21
Pentax smc D FA MACRO 100mm F2.8 WR 589 20
Pentax smc DA 70mm F2.4 Limited 545 20
Pentax smc DA 35mm F2.8 Macro Limited 700 20
Pentax smc FA 50mm F1.4 450 20
Pentax smc PENTAX D FA 50mm F2.8 Macro 444 19
Pentax smc DA 35mm F2.4 AL 220 19
Pentax smc DA 40mm F2.8 Limited 360 17
Pentax smc DA Star 200mm F2.8 ED (IF) SDM 1200 17
Pentax smc DA Star 300mm F4 ED (IF) SDM 1400 17
Pentax smc DA 40mm f2.8 XS 250 17
Pentax smc PENTAX DA 14mm F2.8 575 15
Pentax smc DA 15mm F4 ED AL Limited 510 15
Pentax smc DA 21mm F3.2 AL Limited 650 15

Sigma 35mm F1.4 DG HSM A Pentax 899 12
Pentax smc PENTAX D FA 50mm F2.8 Macro 444 10
Pentax smc DA 35mm F2.8 Macro Limited 700 10
Pentax smc FA 50mm F1.4 450 10
Pentax smc DA 50mm f1.8 249 10
Pentax smc DA 35mm F2.4 AL 220 9
Pentax smc DA Star 55mm F1.4 SDM 640 9
Pentax smc DA 21mm F3.2 AL Limited 650 9
Pentax smc DA 70mm F2.4 Limited 545 9
Pentax smc D FA MACRO 100mm F2.8 WR 589 8
Pentax smc DA 15mm F4 ED AL Limited 510 8
Pentax smc DA 40mm F2.8 Limited 360 8
Pentax smc DA Star 300mm F4 ED (IF) SDM 1400 8
Pentax smc DA 40mm f2.8 XS 250 8
Pentax smc PENTAX DA 14mm F2.8 575 7
Pentax smc DA Star 200mm F2.8 ED (IF) SDM 1200 7

 

If you’re looking for a similar angle of view of a 35mm on a APS-C camera, then you would need a 24mm, though Pentax currently offer only zooms that cover that focal length.

The firm’s Pentax smc DA 35mm f2.8 Macro Limited performs well but $700 it’s not the best value proposition in that focal length. The slightly faster 35mm f2.4 AL model is just $220 and scores 9P-Mpix in our Sharpness test, though bear in mind it lacks the sturdy metal construction and 1:1 life size reproduction capability of the macro model.

Wide-angle lenses don’t perform quite as well as the less demanding 50-85mm models, although the Pentax 21mm f/3.2 AL Limited scores quite well, with a DxOMark score of 15, and a Sharpness score of 9 P-Mpix.


Pentax smc PENTAX DA 16-45mm F4 ED AL 335 17
Pentax smc PENTAX DA Star 16-50mm F2.8 ED AL (IF) SDM 736 16
Pentax smc DA 12-24mm F4.0 ED AL (IF) 700 16
Pentax smc PENTAX DA 18-55mm F3.5-5.6 AL II 125 15
Pentax smc PENTAX DA 55-300mm F4-5.8 ED 475 15
Pentax smc Pentax DA 18-250mm F3.5-6.3 ED AL [IF]  
499 13
Tamron SP 10-24MM F/3.5-4.5 Di II LD Aspherical IF Pentax 499 13
Sigma 18-200mm F3.5-6.3 II DC OS HSM Pentax 349 13
Tamron SP AF 28-75mm F/2.8 XR Di LD Aspherical [IF] Pentax 499 13
Pentax smc DA 18-270mm F3.5-6.3 ED SDM 749 13
Pentax smc PENTAX DA 50-200mm F4-5.6 ED 261 12
Tamron AF18-200mm F/3.5-6.3 XR Di-II LD ASPHERICAL (IF) MACRO Pentax 645 9

 

The price of $650 is fast approaching that of $736 Pentax smc PENTAX DA Star 16-50mm f2.8 ED AL (IF) SDM that’s not only more versatile, and slightly faster but performs similarly (scoring an average of 9P-Mpix and a DxOMark score of 16.

If price is an issue then consider the Pentax smc PENTAX DA 16-45mm f4 ED AL. It’s priced at $335, and scores 8P-Mpix and an overall DxOMark score of 17 points.

Both those models are the best performing zooms. Best value is the 18-55mm f/3.5-5.6 AL II starter lens but that’s often bundled with the camera.


 

Pentax smc PENTAX DA Star 16-50mm F2.8 ED AL (IF) SDM 736 9
Pentax smc PENTAX DA 16-45mm F4 ED AL 335 8
Pentax smc DA 12-24mm F4.0 ED AL (IF) 700 8
Pentax smc Pentax DA 18-250mm F3.5-6.3 ED AL [IF]  
499 7
Pentax smc PENTAX DA 55-300mm F4-5.8 ED 475 7
Pentax smc PENTAX DA 18-55mm F3.5-5.6 AL II 125 6
Tamron SP 10-24MM F/3.5-4.5 Di II LD Aspherical IF Pentax 499 6
Sigma 18-200mm F3.5-6.3 II DC OS HSM Pentax 349 6
Pentax smc DA 18-270mm F3.5-6.3 ED SDM 749 6
Pentax smc PENTAX DA 50-200mm F4-5.6 ED 261 5
Tamron SP AF 28-75mm F/2.8 XR Di LD Aspherical [IF] Pentax 499 5
Tamron AF18-200mm F/3.5-6.3 XR Di-II LD ASPHERICAL (IF) MACRO Pentax 645 4

If sharpness is the only criteria on which to make a judgment then the Pentax smc PENTAX DA Star 16-50mm f2.8 ED AL (IF) SDM comes out top of those analyzed.  However, at less than half the price the similar 16-45mm (24-75mm equivalent) is the better performer overall (with a DxOMark score of 17 points, however it’s a stop slower at maximum aperture.

For those looking for advice on portrait lenses the Pentax smc DA 50mm f1.8 is hard to beat, although as the equivalent to a 77mm lens this and the other 50-55mm lenses maybe a little short. As the equivalent to a 105mm the APS-C 70mm f/2.4 Limited performs well and doesn’t command too high a price as a premium series lens.

Pentax smc DA Star 55mm F1.4 SDM 640 23
Pentax smc DA 50mm f1.8 249 21
Pentax smc DA 70mm F2.4 Limited 545 20
Pentax smc FA 50mm F1.4 450 20
Pentax smc PENTAX D FA 50mm F2.8 Macro 444 19

 

The best performing standard zoom in our database is the $335 Pentax smc PENTAX DA 16-45mm f/4 ED AL with a DxOMark score of 17 points. However, while it was only introduced in 2003, that lens can be difficult to find new, being replaced by the $736 16-50mm f/2.8 and the $599 17-70mm f/4 AL (IF) SDM (not yet reviewed). Although the 16-50mm f/2.8 ED is a good performer on the K-50 the DxOMark score is held back slightly due to high levels of chromatic aberration, but in all other respects it would make a good choice.


 

Pentax smc PENTAX DA 16-45mm F4 ED AL 335 17
Pentax smc PENTAX DA Star 16-50mm F2.8 ED AL (IF) SDM 736 16
Pentax smc PENTAX DA 18-55mm F3.5-5.6 AL II 125 15
Tamron SP AF 28-75mm F/2.8 XR Di LD Aspherical [IF] Pentax 499 13

High-ratio zooms, or super-zooms as they’re often called, generally don’t perform well optically compared to more modest zoom models but what they lose in performance they make up for in convenience. The Pentax smc PENTAX DA 55-300mm F4-5.8 ED is the best performing lens of the five models in our database but unless you need the extra length and corresponding third stop extra in lens speed the Pentax smc Pentax DA 18-250mm F3.5-6.3 ED AL [IF] if you can still find it is the more versatile of the two and the best choice if only lens is used.  At $749 the newer SDM (ultrasonic type AF motor) equipped Pentax smc DA 18-270mm F3.5-6.3 ED SDM performs similarly, albeit with a slightly lower average sharpness across the range.

We’re working hard on expanding the range of Pentax lenses in our database, but we’re interested to know if there are certain models that you would like to see reviewed first. Please leave your recommendations in the comments section below.


Pentax smc PENTAX DA 55-300mm F4-5.8 ED 475 15
Pentax smc Pentax DA 18-250mm F3.5-6.3 ED AL [IF]  
499 13
Sigma 18-200mm F3.5-6.3 II DC OS HSM Pentax 349 13
Pentax smc DA 18-270mm F3.5-6.3 ED SDM 749 13
Pentax smc PENTAX DA 50-200mm F4-5.6 ED 261 12
Tamron AF18-200mm F/3.5-6.3 XR Di-II LD ASPHERICAL (IF) MACRO Pentax 645 9