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After a few years 'struggling' with the 24-85 sold all my lenses and invested in better and faster glass. One of these new lenses was the Canon EF 17-40 f/4 L USM. There can be no doubt that this lens is an excellent lens and all test reports confirm that it barely suffers from any aberrations that some other wide angle lenses suffer from like pin cushioning, barrel distortion, chromatic aberration etc. In fact the only two things I ever thought where 'bad' about it was the fact that it was 'only' f/4 when all my other lenses were now f/2.8 and the price, £520 is a lot to spend on any lens. At the time I bought this lens though there really wasn't much else to choose from, at least not much that was as sharp or fast.
I used this lens for a few years but during this time companies like Canon and Sigma were developing wider lenses and I started to see the results they could capture. One lens that particularly grabbed my attention was the Sigma 10-20mm f/4-5.6 EX DC HSM.
The biggest problem I've noticed with super wide angle lenses is the amount of barrel distortion that they suffer from. To me I couldn't see the point in capturing a super wide horizon if that horizon curved or if you photographed a building it looked like the building was both squashed and falling away from you. Indeed some of the photos I had seen shot with the Sigma 10-20 suffered from these problems but there were still many shots that, thanks to the incredibly wide field of view that this lens offers, just grabbed me. It therefore didn't take me long to decide that I wanted to buy this lens. Now at this stage I had always assumed that I would buy the Sigma 10-20 and keep the Canon 17-40 and that I would pretty much only take the Sigma with me when I was specifically going to shoot landscapes, the first time I used the Sigma though would change all of that.
Whenever I buy a new lens I take it down to the local seafront to see how it performs. Having walked the seafront hundreds of times and taken thousands of photos there I can quickly determine a new lens's strengths and weaknesses. So on the 13th April 2008 I take my new lens for it's first outing.
My first stop was at Worthing Pier. I had previously shot this very scene about a year ago using my 17-40 but this time, using the 10-20, the first thing that struck me was just how wide 10mm actually is! It's really, really wide. The pier, even though I was standing on it, seemed to just shrink in the frame which completely changes the feel of the shot because the pier no longer seems to be the main focus. This is not necessarily a bad thing and the super wide field of view does give the advantage of capturing lots of sky and foreground if desired. For example, had the sky been more dramatic, the sun had not been directly overhead and perhaps the pier had been illuminated all of these elements combined with such a wide field of view could have produced a very captivating image.
The one thing that this shot did immediately confirmed to me though was what I had always suspected about this lens and that is that it very much suits some subjects but is entirely wrong for others due to the way subjects just seem so far away.
For this next shot I walked just a few paces to along the seafront to where there was a large pile of marker buoyes. In truth this shot didn't require the use of a wide angle lens at all but I wanted to test how flexible the Sigma 10-20 really was. Too often I think photographers, including myself, only reach for a wide angle lens when they shoot landscapes or are indoors. Composing this shot was a little tricky with such a wide lens as on all sides around the bouyes were ugly metal crowd barriers which I didn't want in the frame. Interestingly I did take this same shot using my Sigma 24-70 but much preferred this shot from the 10-20. Being that the subject really fills the frame in this shot it really did show just how sharp this lens really is. In terms of sharpness I really would be hard pushed to point out any difference between the Sigma 10-20 and my Canon 17-40.
One of the things I was concerned about when using this lens was converging verticals where buildings look like they are falling away from you. Despite how the image opposite may look, this lens suffers horribly from converging verticals. That is unless you keep the lens perfectly level in which case, as this shot shows, there aren't any converging verticals at all. This does perhaps limit the lens use but it also does give a lot of creative potential allowing you to use converging verticals creatively be accentuating height and distorting perspectives etc. In the right hands, perhaps not mine, this lens is capable of very creative results. In the wrong hands or in the hands of someone who doesn't yet understand how to utilise this lens to it's full potential, you could end up with a lot of shots that will just look very odd.
Worthing Beach is also home to a small fishing community that sell their daily catch on the beach. It was here that I found some of their nets that had been left to dry in the sun. With so much fine detail I thought that this would be another good chance to test how sharp the Sigma 10-20 really was. There really can be no doubt that this lens is actually very sharp and, like all good lenses, required minimal sharpening in Aperture or Photoshop. I haven't seen any direct comparisons with 'scientific' measurements between the Sigma 10-20 and the Canon 17-40 but as I mentioned earlier, in my real world tests the Sigma does appear to be just as good.
For my final two shots I decided to photograph the boats that the fishermen use. It was whilst taking these shots that I realised how this lens forces you to change your shooting style. If you want to fill the frame with your subject you have to get really close to it. In this shot it looks as though I was standing around 3-4ft away from the boat. In reality I was just a few inches away, no more than one foot.
Thanks to the wide field of view I was able to capture foreground detail that puts everything into context and tells more of a story then perhaps just the lobster pots or just the boat would have done.
Summary: The Sigma 10-20 is, in my opinion, a really nice lens. When I first considered buying this lens I had always said that I would use it in addition to my Canon 17-40 f/4 L USM. However after just a few weeks of using the Sigma 10-20 I realised that. for my style of photography, I'd rarely actually use the 17-40 any more and as my camera bag is heavy enough as it is I couldn't face the idea of lugging yet another lens around with me and so I took the decision to sell the 17-40. In terms of image quality I honestly feel that the Sigma is just as good as the Canon. That said, in terms of things like barrel distortion the Canon is vastly superior but at the sacrifice of width. The simple fact of the matter is that the difference between 10mm and 17mm is quite staggering and for me the extra width was worth the sacrifice of barrel distortion especially when if you keep the camera level, barrel distortion is pretty minimal and when the camera isn't level you can use it creatively. The other doubt I had about the Sigma 10-20 was the fact that it was slower than my Canon 17-40. The 17-40 has a max aperture of f/4 throughout it's entire focal range whilst the Sigma 10-20 is f/4-5.6. All of my other lenses are f/2.8 straight through and truth be told I would love to have an f/2.8 wide angle lens too but the Canon 16-35 f/2.8 at over £1000 is simply out of my budget and it's 'only' 16mm. Also for me personally I do tend to mainly use wide angle lenses for landscapes and the types of shots where you want and need a large depth of field, therefore in reality I'm seldom going to need apertures larger than f/8 so f/4-5.6 is going to be absolutely fine for 99.8% of all the shots I'd ever want to take using this lens.
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