January 2007 | Margaret Brown
A capable wide-angle zoom lens for Sony's Alpha DSLR-A100 camera.
RRP: $1149
Rating (out of 10):
- Build: 8.5
- Handling: 8.5
- Image quality: 8
- OVERALL: 8
Sony's DT 11-18mm super wide zoom lens represents a minor evolution of the 11-18mm lens released by Konica Minolta in mid-2005 for the Dynax 5D and 7D cameras. Its DT design is ideally suited for the APS-sized CCD imager of these now defunct models - and also for the Sony Alpha A100 camera. Used on the A100 it provides angles of view between 104 and 76 degrees, which is equivalent to 16.5mm to 27mm on a 35mm camera. This is quite wide for the smaller sensor.
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Sony's DT 11-18mm super wide zoom lens represents a minor evolution of the 11-18mm lens released by Konica Minolta in mid-2005 for the Dynax 5D and 7D cameras. Its DT design is ideally suited for the APS-sized CCD imager of these now defunct models - and also for the Sony Alpha A100 camera. Used on the A100 it provides angles of view between 104 and 76 degrees, which is equivalent to 16.5mm to 27mm on a 35mm camera. This is quite wide for the smaller sensor.
The lens itself has similar specifications to the Tamron SP AF11-18mm F/4.5-5.6 Di II LD Aspherical [IF] lens but lacks its AF/MF switch and the characteristic Tamron gold band. Both lenses consist of 15 separate elements, three of them aspherical, arranged in 12 groups and both feature special coatings to minimise back-scatter and flare.
Seven blades are used in the aperture ring to produce a circular aperture, which Sony claims delivers attractive-looking out-of-focus areas in shots. The large depth of field with this lens makes it difficult to prove this contention - even at the 18mm setting.
Maximum apertures are smaller than those on the Canon EF-S 10-22mm lens, but that's the penalty you pay for a lightweight zoom lens. The focal length range is also shorter - but it meshes in well with the 18-55mm kit lens supplied with the camera. We found vignetting to be slightly less with the Sony lens. Sony's built-in anti-shake system also allows you to shoot at slower shutter speeds, although with such wide angles of view, camera shake is seldom a problem.
The zoom and manual focusing rings moved smoothly and autofocusing was reasonably fast. However, you can't reach the focusing ring when the lens hood is reversed, which is occasionally inconvenient. The lens hood, when fitted, proved effective at reducing most flare.
Imatest testing showed the DT 11-18mm to be a good match for the Sony DSLR A100's sensor. We achieved the highest resolutions at around f8, with a slight fall-off in sharpness between the centre and edge of the field. However, most users would be hard pressed to see much difference in overall sharpness across the aperture range when the lens is in general use. Lateral chromatic aberration was so low as to be negligible.
As expected, some rectilinear distortion was noticeable at the widest focal length but it's modest for an ultra-wide lens. It was negligible in landscape shots and only marginal with closer subjects. Slight vignetting was observed when polarising filters were attached and when flash was used with the widest lens setting. But neither problem would be serious for general photography. Internal focusing allows the DT 11-18mm lens to be used with angle-critical polarisers and graduates.
IMATEST GRAPHS
SAMPLE IMAGES
The DT 11-18mm is excellent for landscape photography.
It also provided some interesting angled shots.
Flare was well controlled ...
... even with strong backlighting.
Focal length range: 11-18mm in 35mm format (16.5-27mm on A100)
Minimum aperture: f/22-29
Lens construction: 15 elements in 12 groups
Minimum focus: 0.25 m
Filter size: 77 mm
Dimensions (Diameter x L): 83 x 80.5 mm
Weight: 360 grams