SMC Pentax-DA* 50-135mm f/2.8 ED [IF] SDM Lens Review

Gary Wolstenholme reviews the Pentax DA* 50-135mm f/2.8 ED [IF] SDM, a bright f/2.8 constant aperture telephoto-zoom lens.

Posted: 16/06/2014 - 11:42

Handling and Features
Performance
Verdict
Specification
 

This 2.7x telephoto zoom lens provides an angle of view roughly equivalent to the popular 75-200mm range on a 35mm format camera. It sports a fast f/2.8 maximum aperture throughout the zoom range, silent focusing and costs around £850. Being a DA* lens, it is one of Pentax's premium optics, as signified by the gold ring around the lens barrel. In this review we'll see how it performs.
 

Pentax DA* 50-135mm f/2.8ED [IF] SDM Handling and Features

The build quality of this lens is excellent, with high quality plastics used for the construction of much the lens barrel and the bayonet being constructed from metal. It sports a weather and dust resistant construction and isn't overly heavy for an optic with a constant f/2.8 aperture, weighing around 765g. As a result, it balances well with the Pentax K-5 IIs body used for testing.

The lens barrel doesn't extend, as focusing and zoom are performed internally and the filter thread does not rotate. This makes it perfect for use with polarising and graduated filters. A deep petal-shaped hood is supplied with the lens that attaches to the front of the lens via a bayonet fitting.

The manual focusing ring doesn't rotate during auto-focus and manual adjustments can be applied at any time. Manual focusing action is not as smooth as you may expect from a lens of this level and price, on the sample used for testing. Even so, there is enough damping to make applying manual focus adjustments easy. Auto focus is powered by a silent motor in the lens, which is quick to lock onto subjects. The minimum focus distance of one metre is fairly standard for a lens of this type.

Pentax DA* 50-135mm f/2.8ED [IF] SDM Performance

At 50mm and maximum aperture, sharpness approaches excellent levels in the centre of the frame, and falls just short of good levels towards the edges of the frame. Stopping down improves performance across the frame with peak levels of clarity being achieved between f/5.6 and f/8. Here sharpness is outstanding in the centre and excellent towards the edges of the frame.

Zooming to 70mm results in similar performance at maximum aperture, with very good sharpness being produced in the centre of the frame and fairly good clarity towards the edges. Peak performance is realised at f/8 at this focal length. Here sharpness is outstanding across the frame.

Finally at 135mm, sharpness falls just short of very good levels at maximum aperture and clarity towards the edges of the frame is fair. Stopping down just one stop to f/4 results in outstanding performance in the centre of the frame, but it takes until f/8 until sharpness reaches very good levels towards the edges of the frame.

SMC PENTAX-DA* 50-135mm f/2.8 ED [IF] SDM MTF Charts

Chromatic aberrations are well controlled for the most part; remaining well under one pixel width at all settings bar 50mm and f/22. As a result, fringing should rarely be an issue, even in harsh crops from the edges of the frame, or in large prints with high contrast edges.

SMC PENTAX-DA* 50-135mm f/2.8 ED [IF] SDM Chromatic Aberration Charts

Falloff of illumination is well controlled for a lens of this range and maximum aperture. At 50mm the corners of the frame are 0.8 stops darker than the image centre and at 135mm the corners are 1.2 stops darker. Visually uniform illumination is achieved with the lens stopped down to f/5.6 or beyond throughout the zoom range.

Distortion is fairly mild at either end of the zoom range. Imatest detected 0.7% barrel distortion at 50mm, which is replaced by 1.68% pincushion distortion at 135mm. The distortion pattern is uniform across the frame, which should make it relatively easy to apply corrections in image editing software afterwards if straight lines are necessary.

During testing, this lens proved itself resistant to flare and contrast levels are good, even when shooting into the light. The petal-shaped hood does a decent job of shading the lens from extraneous light that may cause issues.

SMC PENTAX-DA* 50-135mm f/2.8 ED [IF] SDM Sample Photos

Value For Money

Being priced at around £850, this lens is priced quite reasonably for a manufacturer's own tele-zoom with a constant f/2.8 aperture, especially as there aren't currently any direct equivalents available for Pentax cameras.

Pentax DA* 50-135mm f/2.8ED [IF] SDM Verdict

This lens has been around a while now, but it still manages to hold its own well against the very latest lenses available from other manufacturers. It delivers very good sharpness in the centre of the frame at maximum aperture, and excellent sharpness across the frame when stopped down. The price of around £850 isn't too much to ask for a quality manufacturer’s own-brand lens either, especially given the excellent build and weather sealing.

Members gallery photos using: smc PENTAX-DA* 50-135mm F2.8 ED [IF] SDM

jambodog6a jambodog6a

30 posts
10 years
Norwich

Posted 17/10/2015 - 14:45 Link

I have a 50 135* mm F2.8 SDM is anybody know the date they came out I think mine is quite old
Stan J

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