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HD Pentax-FA 150-450mm f/4.5-5.6 ED DC AW Lens Review

Gary Wolstenholme reviews the new Pentax HD PENTAX-D FA 150-450mm f/4.5-5.6 ED DC AW telephoto zoom lens for APS-C and FF cameras.

Posted: 22/04/2015 - 11:02

Handling and Features

HD PENTAX D FA 150 450mm F4This 3x super-telephoto zoom lens covers an interesting zoom range which fills a long established gap in the Pentax line-up, as telephoto zoom lenses have been thin on the ground, with many Pentax camera owners relying on offering from third-party lens manufacturers. Another point of interest is the fact this lens sports an image circle large enough to cover a full frame sensor and provides a focal length roughly equivalent to a 230mm - 690mm range when used with Pentax APS-C DSLRs. It's interesting that Pentax/Ricoh have chosen to release this lens with full frame coverage, as all of their current DSLRs are fitted with APS-C size sensors. This means there may be truth in the announcements that a full frame Pentax DSLR will be available by the end of this year. It sports silent focusing, weather sealing and HD anti-reflective lens coatings and a price at launch of around £2000. In this review, we'll take a look at how this lens performs on an APS-C Pentax DSLR, it will be interesting to see how the lens performs in the future on a full frame camera, when one is finally released.

Pentax HD PENTAX-D FA 150-450mm f/4.5-5.6 ED DC AW Handling and Features

HD PENTAX D FA 150 450mm F4The build quality of this lens is very good indeed, with a combination of metal and high-quality plastics used for the construction and the bayonet being made of metal. It sports a dust and moisture-resistant construction and weighs 2kg. As a result, it balances fairly well with the Pentax K-3 body used for testing.

The lens barrel extends by around three inches at maximum zoom and as focusing is performed internally, the 86mm filter thread does not rotate, which makes it perfect for use with polarising and graduated filters, if you can find them in that size. A deep circular hood is supplied with the lens that attaches to the front via a bayonet fitting and a removable tripod mount can also be clipped to a rotating section on the lens. A switch to lock the lens at 150mm during transport is provided, but it would've been nice to see this implemented in a way that could lock the lens at any focal length, as the zoom creeps forward or back as the lens is tilted, which could make shooting from a tripod difficult.

HD PENTAX D FA 150 450mm F4
The manual focusing ring doesn't rotate during auto-focus and manual adjustments can be applied at any time. A focus preset mode is also available, accessed via controls on the side of the lens. Manual focusing action is smooth and well damped, which makes applying fine adjustments a pleasure. Autofocus is quick and proved to be accurate during testing. The minimum focus distance of 2metres is typical for a lens of this type.

HD PENTAX D FA 150 450mm F4

Pentax HD PENTAX-D FA 150-450mm f/4.5-5.6 ED DC AW Performance

At 150mm, sharpness is already excellent in the centre of the frame, with performance towards the edges reaching very good levels. Stopping down to f/8 results in outstanding sharpness across the frame at this focal length.

Zooming to 300mm and maximum aperture, sharpness drops to good levels across the frame. Performance improves with stopping down, reaching excellent levels across the frame by f/8.

Finally, at 450mm, sharpness actually increases at maximum aperture and is incredibly consistent across the frame. Here sharpness levels are very good levels across the frame and stopping down to f/8 results in peak performance.

How to read our MTF charts

The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges.

The scale on the left side is an indication of actual image resolution and sharpness as LW/PH and is described in detail above. The taller the column, the better the lens performance.

For this review, the lens was tested on a Pentax K-3 using Imatest.

Chromatic aberrations are well controlled between 150mm and 300mm, with fringing increasing dramatically at 450mm. At 450mm fringing exceeds 1.75 pixel widths towards the edges of the frame at maximum aperture, which may become visible, especially in images containing areas of high contrast.

How to read our CA charts

Chromatic aberration (CA) is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.

Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more.

For this review, the lens was tested on a Pentax K-3 using Imatest.

Falloff of illumination towards the corners of the frame is well controlled. At 150mm and maximum aperture, the corners are 0.4 stops darker than the image centre increasing to a difference of 0.5 stops at 450mm. Visually uniform illumination is achieved with the aperture stopped down to f/8 or beyond.

Distortion is very well controlled at both ends of the zoom range. Imatest detected 0.6% pincushion distortion at 150mm, which decreases to 0.01% pincushion distortion at 450mm. The distortion pattern is uniform across the frame, which should make it relatively easy to apply corrections in image editing software afterwards if absolutely straight lines are necessary.

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

Value For Money

Being priced at around £2000, this lens is priced roughly in line with similar offerings from other manufacturers for their own camera systems.

Sigma's 150-500mm f/5-6.3 DG HSM may make a viable alternative, especially with it sporting a slightly more telephoto reach, at the expense of a slower maximum aperture. Although it lacks weather sealing, it is substantially cheaper, being available for around £600.

Pentax HD PENTAX-D FA 150-450mm f/4.5-5.6 ED DC AW Verdict

Pentax camera owners have been crying out for a decent telephoto zoom option, similar to those offered by other camera manufacturers, for an age and finally their prayers have been answered with this lens.

Although it may seem a bit pricey at first glance, this lens costs a similar amount to equivalents from other camera manufacturers and performs as well as you'd expect for a top of the range lens of this ilk.

Even though this lens will probably win over many fans who own existing Pentax DSLRs, it will also be interesting to see how it performs on a full frame camera, when Ricoh/Pentax make one available.

Pentax HD PENTAX-D FA 150-450mm f/4.5-5.6 ED DC AW Pros

  • Very good sharpness
  • Weather and dust resistant construction
  • Good build quality
  • Silent focusing
  • Full time manual focus override
  • Low falloff and distortion

Pentax HD PENTAX-D FA 150-450mm f/4.5-5.6 ED DC AW Cons

  • Zoom creeps as lens is tilted and no lock only functions at 150mm
  • High CA levels at 450mm

Features: 4.5/5
Handling: 4.5/5
Performance: 4.5/5
Value: 4.5/5
Overall Verdict: 4.5/5

Pentax HD PENTAX-D FA 150-450mm f/4.5-5.6 ED DC AW Specifications

Manufacturer Pentax
Lens Mounts Pentax KAF3
Focal Length 150mm - 450mm
Angle of View 3.6 - 10.7
Max Aperture f/4.5 - f/5.6
Min Aperture f/22 - f/27
Filter Size 86mm
Stabilised No
35mm equivalent 230mm - 690mm
Internal focusing Yes
Maximum magnification No Data
Min Focus 200cm
Blades 9
Elements 18
Groups 14
Box Contents
Box Contents Hood, Lens cap, Mount cap, Lens Case, Tripod Mount
Weight 2000g
Height 241.5mm

Members gallery photos using: HD PENTAX-D FA 150-450mm F4.5-5.6 ED DC AW

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