The Sony DT 11-18mm delivers an ultra wide angle range which perfectly complements the standard DT 18-70mm kit lens. It essentially takes over where the kit lens stops, capturing a progressively wider field of view until you find yourself at 11mm and enjoying 104 degree coverage. Certainly if you’ve ever zoomed-out your Alpha general purpose lens and wished it went wider still, then this is a lens you should be considering very seriously.

In its favour the DT 11-18mm suffers from little geometric distortion or light fall-off considering its ultra wide range, and it’s always good to find a lens hood included as standard – if only Canon would do the same. On the downside though, there’s noticeable softening in the extreme corners, a manual focusing ring which turns during AF, and a relatively slow focal ratio of f4.5 when it’s zoomed-out to 11mm.

The optical range is also only 1.6x, which seems a little modest compared to rival ultra-zooms from Sigma, Nikkor and Canon which boast 2x or 2.2x ranges. And while this applies to most Sony lenses, the AF can be slow and noisy – certainly it’s a world apart from the quick and quiet focusing of, say Canon’s EF-S 10-22mm or the Nikkor 12-24mm AF-S.

But if you’re an Alpha owner, the DT 11-18mm is one of the few ultra wide angle lenses available, so you have to learn to love the good points and overlook the bad. There are however two alternatives you should also consider.

The Tamron 11-18mm f4.5-5.6 has a virtually identical specification to the DT 11-18mm, and while both Sony and Tamron claimed they didn’t produce lenses for each other, the likeness of this particular model – inside and out – is uncanny. The only differences we’re aware of are the direction of the focusing ring and confirmed support for ADI flash on the Sony model. The Tamron version does however come in a little cheaper.

Then there’s the Sigma 10-20mm f4-5.6, offering a 2x range that gets slightly wider and longer than either the Sony or Tamron models; it’s also a little brighter when zoomed-out and additionally features HSM for quicker and quieter focusing. We’ve heard both good and bad reports of this lens, suggesting quality control issues, but it seems if you get a good copy, you’re onto a winner.

Ultimately if you’re after an ultra wide angle lens for an Alpha DSLR, your choice will boil down to these three models. We’ve not tested the Tamron or Sigma models so can’t comment on how they compare, although if you heard over to the Cameralabs forums, several members have reported on using both.

We can however say if you’re willing to accept some softness in the extreme corners and a modest focal range, then the DT 11-18mm will be a good option for Alpha DSLR owners wanting to indulge in some ultra wide angle photography. Check out our DT 11-18mm video tour for a demonstration of its design, coverage and AF performance.

Good points Ultra-wide angle coverage. Relatively low vignetting and distortion. Range complements kit lens. Comes with lens hood. Bad points Softness in extreme corners. Small 1.6x optical range and f4.5 at 11mm. AF noise and speed similar to kit lenses. Manual focus ring turns during AF.		Scores (relative to other Sony zooms)
		Build quality: Optical quality: Specification: Value: Overall:	17 / 25 20 / 25 17 / 25 18 / 25 72%