Sigma 18-250mm f/3.5-6.3 DC Macro OS HSM Lens Review

Handling and features
Performance
Verdict
Specification


This 13.8x superzoom lens is compatible with Canon, Nikon, Pentax, Sony and Sigma DSLRs that have an APS-C sized sensor or smaller. On a Canon APS-C format camera, this lens provides an angle of view equivalent to a 28.8-400mm lens on a 35mm camera and costs around £400.

This is the first lens from Sigma to sport their newly developed Thermally Stable Composite material, which professes to allow for more compact, lightweight lens designs. Even though this lens has Optical Stabilisation, it is still 160g lighter than its non-stabilised predecessor.

Sigma 18-250mm f/3.5-6.3 DC Macro OS HSM Handling and features

For a lens that covers an impressive 13.8x zoom range, the Sigma 18-250mm DC Macro OS HSM collapses down very small indeed, and weighs only 470g. You'd be forgiven for getting it mixed up with one of the standard 18-135mm kit lenses manufacturers offer. The thermally stable composite material used for much of the lens barrel doesn't look overly special, but it feels tough, despite its light weight. A metal lens mount provides reassurance that this lens is built well. The light weight and small size make this an ideal 'walkabout' companion for entry level bodies and it even feels at home on the Canon EOS 7D used for testing.


Sigma 18-250mm Lens extended

Sigma's HSM focusing motor provides fast, silent and accurate autofocus throughout the zoom range. The lens rarely hunts for a lock, even in dim lighting conditions. This lens doesn't support full time manual focus override, unlike higher specified Sigma lenses do. Focusing is performed internally, so the 62mm filter ring does not rotate, which makes this lens ideal for use with graduated and polarising filters.

The optical stabilisation system fitted to this lens promises sharp hand held photos at shutter speeds up to four stops slower than would normally be possible. The OS system provides a very steady viewfinder image and with care, sharp shots are possible at 1/25sec and 250mm, around three quarters of the time, which is four stops slower than the usual rule of thumb would allow.
 

Sigma 18-250mm f/3.5-6.3 DC Macro OS HSM Performance

As is the case with most superzoom lenses, sharpness at 18mm is excellent in the centre and good towards the edges of the frame at maximum aperture. Although stopping down improves the clarity towards the edges of the frame slightly, it does at the expense of the sharpness in the centre. Peak sharpness is achieved between f/4 and f/8 at this focal length.

With most superzoom lenses, you may expect to see a drop off in performance as the lens is zoomed in. This Sigma 18-250mm optic still holds up well at 80mm, with very good sharpness across the frame at maximum aperture and outstanding clarity across the frame at f/8.

Finally at 250mm, sharpness does drop off a little, but at maximum aperture, sharpness is still good in the centre of the frame and fairly good towards the edges. Peak quality for this focal length is achieved at f/11, where sharpness is excellent in the centre, and good towards the edges.

 

Resolution at 18mm

Resolution at 80mm

Resolution at 250mm

How to read our charts The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column. The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple. For this review, the lens was tested on a Canon EOS 7D using Imatest.

Again, for a superzoom, Chromatic aberrations are very well controlled throughout the zoom range. Fringing can be at its strongest at 250mm near the edges of the frame, but even then levels are still below one pixel width.

Chromatic aberration @ 18mm

Chromatic aberration @ 80mm

Chromatic aberration @ 250mm

How to read our charts Chromatic aberration 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 Canon EOS 7D using Imatest.

Falloff of illumination towards the corners of the frame is well controlled throughout the zoom range. At 18mm the corners are only 1.38 stops darker than the image centre and visually uniform illumination is achieved by f/5.6. At 250mm the corners are only 0.99 stops darker than the centre and all discernible traces of vignetting are gone by f/11.

Distortion is also well controlled for a superzoom lens, with a fairly noticeable level of 3.04% barrel distortion at 18mm and 1.28% pincushion at 250mm. The distortion pattern remains uniform across the frame throughout the zoom range, so it should be relatively straightforward to correct in image editing software afterwards.

No issues out of the ordinary were had regarding flare and loss of contrast when shooting into the light. When shooting wide open at 250mm into the light, contrast does drop off noticeably, but this can be improved by stopping down.

Sigma 18-250mm f/3.5-6.3 DC Macro OS HSM Sample Photos

Value for Money

Being priced at around £400, this lens is cheaper than 18-200mm alternatives from most camera manufacturers, plus it delivers decent quality and an extra 50mm of reach at the telephoto end. I belive this represents good value, plus as this lens is newly released, I imagine the street price may drop in time too. The Sigma 18-250mm f/3.5-6.3 DC Macro OS HSM lens is available for pre-order from Harrison Cameras.

Sigma 18-250mm f/3.5-6.3 DC Macro OS HSM Verdict

Superzoom lenses are often full of compromises, but in this 18-250mm lens from Sigma, the compromises are few and far between. It may be the case that shorter zoom ranges may yield better performance overall, but if you're after a convenient all-in-one lens for travel, then the sharpness delivered by this lens certainly makes it worthy of serious consideration, especially when compared to manufacturer’s own superzoom offerings. It's lighter, more compact, cheaper, offers more reach and performs about as well, if not better in some areas.

	The Sigma 18-250mm f/3.5-6.3 DC Macro lens is a convenient all-in-one lens delivers sharp results making it worthy of serious consideration

Sigma 18-250mm f/3.5-6.3 DC Macro OS HSM Pros

Very good performance for a superzoom
Effective optical Stabilisation
Compact size
Light weight
Good build quality

Sigma 18-250mm f/3.5-6.3 DC Macro OS HSM Cons

f/6.3 max aperture at 250mm is relatively slow
No full time manual focus override (which isn't really much of an issue)

FEATURES
HANDLING
PERFORMANCE
VALUE FOR MONEY
OVERALL

Sigma 18-250mm f/3.5-6.3 DC Macro OS HSM Specifications

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