Gary Wolstenholme reviews the Pentax DA* 60-250mm f/4 ED [IF] SDM telephoto zoom lens.
Posted: 16/06/2014 - 11:42
Handling and Features
Performance
Verdict
Specification
This 4.2x super-telephoto zoom lens provides an angle of view roughly equivalent to a 90-375mm range on a 35mm format camera. It sports a relatively fast f/4 maximum aperture throughout the zoom range, silent focusing and costs around £1070. In this review, we'll take a look at how this lens performs, and whether it really deserves the DA* premium branding.
Pentax DA* 60-250mm f/4 ED [IF] SDM Handling and Features
The build quality of this lens is very good indeed, with high quality plastics used for much of the lens barrel's construction and the bayonet being made of metal. It sports a weather and dust resistant construction and a manageable weight of just over a kilogramme. As a result it balances very well with the Pentax K-5 IIs body used for testing.
The lens barrel extends by around three inches at maximum zoom. As focusing is performed internally, the filter thread does not rotate, which 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 via a bayonet fitting and a removable tripod mount can also be clipped to a rotating section on the lens.
The manual focusing ring doesn't rotate during auto-focus and manual adjustments can be applied at any time. Manual focusing action is smooth and there is enough damping to make applying adjustments a pleasure. Even though auto focus is powered by a silent motor, it isn't very quick to lock onto subjects, often taking a while to drift into position. The minimum focus distance of 1.1metres is quite close for a lens of this type, allowing for frame filling close up images.
Pentax DA* 60-250mm f/4 ED [IF] SDM Performance
At 60mm, sharpness is already excellent in the centre of the frame at 60mm, with performance towards the edges reaching good levels. Stopping down to f/8 results in excellent sharpness across the frame at this focal length.
Zooming to 135mm and maximum aperture, sharpness drop to good levels in the centre of the frame, with performance towards the edges of the frame falling to fair levels. Clarity in the centre of the frame improves dramatically with stopping down, reaching outstanding levels by f/8, but performance towards the edges of the frame takes longer to catch up, falling just short of excellent sharpness levels at f/11.
Finally, at 250mm, the way this lens performs follows much the pattern at 135mm. At maximum aperture sharpness is good in the centre, but only fair towards the edges of the frame. Sharpness is excellent in the centre between f/8 and f/11 but the lens needs stopping down to f/11 to exceed good levels of clarity towards the edges of the frame.
SMC PENTAX-DA* 60-250mm f/4 ED [IF] SDM MTF Charts
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-5 IIs using Imatest.
Chromatic aberrations are well controlled between 60mm and 135mm, going a bit crazy at 250mm. At 250mm fringing approaches 2.5 pixel widths towards the edges of the frame at maximum aperture, which may become visible, especially in images containing areas of high contrast.
SMC PENTAX-DA* 60-250mm f/4 ED [IF] SDM Chromatic Aberration Charts
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-5 IIs using Imatest.
Impressively, there is no discernable falloff at 60mm and maximum aperture. At 250mm and f/4, the corners are 0.95 stops darker than the image centre and visually uniform illumination is achieved with the aperture stopped down to f/5.6 or beyond.
Distortion is very well controlled at both ends of the zoom range. Imatest detected 0.7% barrel distortion at 60mm, which is replaced by 0.5% pincushion distortion at 250mm. 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 petal-shaped hood does a decent job of shading the lens from extraneous light that may cause issues.
SMC PENTAX-DA* 60-250mm f/4 ED [IF] SDM Sample Photos
Value For Money
Being priced at around £1070, this lens is priced roughly in line with similar offerings from other manufacturers for their own camera systems. Due to the unique combination of focal range and a constant f/4 maximum aperture, there aren't currently any other comparable lenses available for Pentax cameras from third party manufacturers.
Pentax DA* 60-250mm f/4 ED [IF] SDM Verdict
Overall, this isn't a bad lens. It offers a useful zoom range, in a relatively compact and not overly heavy package. It is more than capable of delivering decent, sharp images. Unfortunately, the levels of sharpness aren't of the level that will blow your socks off, especially at maximum aperture. The slow focusing compounds this issue, as taking images of moving subjects is made more challenging by the lethargic focus action. Add in the high levels of fringing at 250mm, and the performance of this optic is very much a mixed bag.
Pentax DA* 60-250mm f/4 ED [IF] SDM Pros
- Good sharpness in the centre at maximum aperture
- Very good sharpness across the frame when stopped down
- Weather and dust resistant construction
- Good build quality
- Silent focusing
- >Full time manual focus override
- Constant f/4 aperture
- Low falloff
Pentax DA* 60-250mm f/4 ED [IF] SDM Cons
- Slow autofocus
- High CA levels
Specifications: SMC PENTAX-DA* 60-250mm f/4 ED [IF] SDM |
||||
| General | ||||
| Focal Type | Tele zoom | |||
| Lens Mounts | Pentax K SMC-DA, Pentax KAF | |||
| Availability | ||||
| Year announced | 2007 | |||
| Discontinued | No | |||
| Dimensions | ||||
| Diameter | 82mm | |||
| Height | 167.5mm | |||
| Weight | 1040g | |||
| Construction | ||||
| Groups | 13 | |||
| Elements | 15 | |||
| Blades | 9 | |||
| Lens | ||||
| Internal focusing | Yes | |||
| 35mm equivalent | 380 - 90mm | |||
| Stabilised | No | |||
| Filter Size | 67mm | |||
| Min Aperture | f/32 | |||
| Max Aperture | f/4 | |||
| Angle of View | 27 - 7° | |||
| Focal Length | 250 - 60mm | |||
| Focusing | ||||
| Macro | No | |||
| Min Focus | 110cm | |||
| Focusing Type | Automatic | |||
| Box Contents | ||||
| Box Contents | Front cap, Rear cap, Lenshood, Soft case, Datachable tripod mount | |||
Members gallery photos using: smc PENTAX-DA* 60-250mm F4 [IF] SDM
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