Sigma 10-20mm f4-5.6 EX DC HSM - Canon fit lens

After a few days of solid use in Iceland: + Minimal c/a, rarely noticeable even if you pixel-peep + Very sharp, probably the sharpest DX ultra-wide. Corners and edges are very good. + The cheapest ultra-wide that you'd actually ever want to use on a DX. - Complex distortion at all focal lengths. Extreme at 10mm. - The longer (16-20mm) range of focal lengths were initially just a nice bonus, but turned out to be essential in Iceland as I couldn't risk swapping lenses when I was out on a windy glacier.=======I was going to get the Tokina 11-16mm f/2.8, or possibly the Nikon 10-24mm f/3.5-4.5. The Tokina is fast, sharp and its only real drawbacks are the lack of width (11mm vs 10mm is a lot actually!), and excessive c/a in the edges and corners (on the 4 samples that I tested). The Nikon is slightly slower than the Tokina, less sharp, and more expensive.At the last minute, a proper photographer convinced me to consider this lens and I have no regrets! In addition to being cheaper than the other ultra-wides for Nikon, it has no noticeable c/a, is very sharp, is compact, and quite lightweight. It does however have significant (but easily corrected) distortion. It may be less sharp than the Tokina in online reviews (not that I've noticed), but certainly makes up for it with clear, c/a-free corners!Having returned several Sigma lenses due to poor image/build quality, I tried hard to fault this one but I really can't. It is a great piece of glass and good value for money too. It is now the second Sigma that I own and regularly use, the other being the 150-500mm Sigmonster.The image quality is lovely and the build quality seems good too. The action is smooth and it doesn't wobble on the mount at all (which my 150-500mm Sigma does, annoyingly). If it broke tomorrow (which I half-expect after the last few Sigmas I tried), I would replace it with another Sigma 10-20mm/f4 without hesitation.

When I was looking at buying a wide angle lens I had three questions in mind:A) How to avoid grey imports / being sold a non genuine lensB) What were the must have accessories required to make full use of the lens (cap, hood, filters)C) Will the low end of the price range will deliver good enough resultsA - I've ordered via Amazon direct, this costed me a few pounds extra. Not sure this is the only way to avoid grey imports but it my case it worked. The only reason for being nervous about grey imports was the comments on faulty items where the warranty claims were rejected by Sigma saying it was grey imports.B - The lens comes with the usual two caps + sun hood + case. This was as described on Sigma's website. Comments on photographers' websites suggested that a polarizing filter was not appropriate for a wide angle lens so I dedided not to add any to my order, saving at least 20GBPC - The lens seems robust and well made. The 10mm focal does really makes a difference. The distortion at low focal distances can be easily corrected via softwares such as Lightroom. The lens is not very sharp. I've tried a couple of shots with small apertures but again the sharpness is definitely not the best of this lens. In fairness to Sigma this is easily predictable from the MTF charts issued by the manufacturer.The built in motor is really quiet and fast (although I use this lens for mainly for buildings so it doesn't make any difference for me)As a conclusion I'm happy with the lens but rating it at 4 as a result of the limited sharpness

This is a very impressive lens for all sorts of reasons. Firstly, and from the minute you open the box you get a feeling of quality. The lens barrel is in a matt finish and looks extremely smart with the appearance, colour and feel of a lens for a Nikon camera. More importantly, it works smoothly and with a quiet efficiency. It achieves focus as quietly as any of my Nikon lenses and I have to say it feels every bit as solid.In terms of image quality it also impresses. So far I have just done a load of test shots around and near my home but the results have been very pleasing. I have encountered some slight chromatic aberration but nothing to cause any concern. In terms of sharpness, again I have been very impressed. Some reviewers have commented upon a slight edge softness. So far I have not been aware of it although it is early days and I have not taken shots in a variety of lighting conditions. Most of my shots have been landscapes in reasonably bright daylight conditions. I cannot fault the sharpness of the lens. In fact, it is probably better than I was expecting given the price.Finally, the most impressive part. You can get this cracking lens at a heavily discounted price (discounts between 40%-50%). If you are in the market for a wide angle zoom that you can carry around all day then you really should consider this one.

I agonised over this buy: there's lots of choice and variation in price. Tokina and Nikon and other Sigma models being the competition. The Tokina 11-16mm f2.8 DXII seems very desirable - fast and sharp by all accounts. The Tokina's 12-24 DXII seems nice too with its AF motor. I guess when the DXI have sold out the DXII will drop in price - currently unless you buy Hong Kong etc they're as expensive as the Nikon. Then there's the Nikon 10-24 f3.5-4.5 which is pretty good but expensive. I like the Sigma 8-16mm f4.5-5.6 too and that's at a good price currently on Amazon for the Nikon but seems there's a lot of variation in quality - great if you get a good one but getting such is awkward online. Lens tennis is not fun. All of these lenses seem cheaper if bought from USA, Hong Kong or now Japan. But given the sample differences in lenses, it can be a right pain to go that way never mind any warranty work issues. I want a lens not shipping bills.I finally decided to go Sigma 10-20mm f4-5.6 from Amazon since it's not too expensive, optically very good, wide enough and well built. My point is made about 'Hong-Kong savings' in that my first copy had a tilted/decentred element so that the right side was soft and the centre to left sharp. Had that been an import, Sigma UK would not have fixed it. As it is, Amazon had a replacement to me the next day. Excellent service.Thankfully, the replacement is fine so far - sharpness/softness seems centred. As others note, corners can be soft wide but sharpen up quickly as you stop down. There's some CA and distortion but these are mostly correctable. Images look sharp with that wide dynamic look such lenses offer. I like it. Summer should be good for this.

It was a choice between this or the Tamrom 10-24, which gives a marginally better optical range, but as the range we all buy these wide-angles for is closer to the 10 mark then the extra headroom afforded by the Tamrom was not a point to be considered, except that it might actually detract from optical perfection, having a wider range.Initial observations are that straight lines stay roughly straight, except for those bowed convergent verticals in extreme camera angles relative to subject - that is, no additional warping due to low grade optics.The build is of a semi-hard rubberised plastic, seems resilient without needing to be solid or metal as was the case years ago before these high-durability plastics were invented. It's not going to bashed about that much, something that costs this much is going to be taken care of! But on the opffchance there's a bump while I'm out and about, the plastic seems more than adequate to protect.Smooth focus, and it also works on the in-between range of SLRs that were current before the new range: that is to say, the new range makes use only of lenses that have their own focusing engine built in, while the previous generation of SLRs could either use this function or enlist a motor built into the camera itself to focus the lens - this works with both types. The older SLRS which only employed the focus motor built into the camera will have to be stepped down to manual-only focus. Hardly a problem at all as the focus is extremely deep anyway.