Superzooms have been around for over a decade and we’ve seen them extend from the likes of the 28-200mm to the 28-300mm for 35mm users, with the 18-200mm appearing when digital SLRs came of age.
Tamron’s latest superzoom takes the zoom range further with an equivalent of around 28-388mm in 35mm terms. This means it covers everything from wide-angle through telephoto and into the territory of the super-telephoto. That’s an amazing feat and what makes it even more incredible is when you take into account how compact the zoom is.
In its ‘closed’ setting, the Tamron measures just over 84mm, which to put into context, is less than 20mm longer than a Canon 18-55mm standard zoom.

So in terms of versatility, there is plenty to admire about the Tamron, as it offers a one-stop solution in terms of the most popular focal lengths. The build quality and handling of the Tamron is good too, and it boasts a metal rear lens mount.
The zoom ring is wide, with a grooved, rubberised grip that’s easy to use and a nice, smooth action. There is also a zoom lock facility, ideal when you’re walking with the camera pointing down, as it prevents the zoom from slowly extending under the influence of gravity.
The manual focus ring, at the front end of the zoom, is a good width and bears a focus distance scale. The minimum focus of 45cm is good, allowing you to fill the frame with relatively small objects.
We tested the Canon-fit lens on an EOS 400D and found its autofocus to be reasonably good. It’s not as quiet as Canon’s own lenses, but the autofocus whir isn’t a real issue. In bright conditions, it zips quickly into focus, but we’d recommend you stick to using multi-point AF as light levels fall, as it can hunt a little if your camera is set to single-point AF, especially once the zoom is beyond around 200mm.

In terms of optical quality, the Tamron delivers good results considering the range. As with other superzooms, it’s sharper at the wide-angle end than at telephoto. At maximum aperture, sharpness is good at the wide end and fair at the tele end. Stop down to f/11 and the level of detail that is captured improves, as you’d expect. Sharpness is very good at the wide-end and good at the tele end.
But to get the best from the lens, you do have to take care with handling. Shake is a real issue, especially when you consider that the zoom has a maximum aperture of f/6.3 beyond 200mm. So we’d recommend you keep an eye on shutter speeds and consider setting ISO 400 to help prevent shake from spoiling your shots.

There is evidence of barrel distortion at the wide end, but it’s not a problem unless you’re shooting a subject that’s very close. Pincushion distortion at the telephoto end is not really an issue. Chromatic aberration is very well controlled, thanks to the use of Low Dispersion (LD) glass.
The big question then is whether spending £400 on an 
18-250mm is better than forking out for a couple of zooms covering a similar range. If convenience is paramount, then the Tamron has plenty going for it, and, so long as you don’t plan to print anything bigger than a 10x8in, you’ll most likely be happy with the results.
However, if you already have an 18-55mm kit lens, you’ll already have covered the wide end of the Tamron’s range and in truth, would most likely find little difference in performance of your standard zoom compared to the Tamron. So, all you need then is a telezoom and there are some good options. Tamron’s 55-200mm, which costs under £100, offers great value, while Sigma’s 70-300mm offers an extended range and very good quality. Of course, this involves the ‘inconvenience’ of carrying around two lenses.
Whether the superzoom represents a better buy for you is a decision only you can make. If the answer is that it does, you can be sure this Tamron is as good as any out there, but with an additional ‘50mm’ on offer at the telephoto end.

VERDICT
The Tamron is a capable superzoom that delivers adequate results when used carefully. Its versatility is impressive, but you should be aware of its restrictions, such as the maximum aperture of f/6.3 from 200mm. It’s best use will be as a travel lens, where its range and compact size are advantageous.

Specifications
Tamron 18-250mm f/3.5-6.3 Di-II LD Asph
Focal length: 18-250mm (35mm 
equivalent: 28-388mm); Maximum aperture: 
f/3.5-6.3;  Minimum aperture: f/22; Angle-of-view: 75°33’–6°23’ (APS-C size equivalent); 

Lens construction: 16 elements in 13 groups; Minimum focusing distance: 0.45m;
Magnification ratio: 1:3.5 (at 250mm);
Diaphragm blades: Seven;
FiIter thread: 62mm; Overall length: 84.3mm; Maximum diameter: 74.4mm;
Weight: 430g; 
Supplied accessory: Hood; AF fittings: 
Canon, Nikon, Pentax/Samsung & Sony
Tamron: 01628 674411; www.intro2020.co.uk