Sigma 12-24mm f/4.5-5.6 EX DG HSM Review

You may be surprised to discover that I use a relatively cheap ($690) Sigma lens for my 1Ds3. But the Sigma 12-24mm f/4.5-5.6 EX DG HSM is a truly unique lens: it is currently the widest rectilinear wide-angle for fullframe, at 12mm, it gives an amazing angle of view of 122 degrees! By comparison, the widest wideangle zoom of Canon, the 16-35 f/2.8 II, has "just" an angle of view of 107 degrees - an huge difference, that has led me to choose the Sigma.

Lens Specifications

Description

The 12-24 has the built quality of the best Sigma EX lenses: it feels very sturdy, even tought it is not on par with the most recent Canon L lenses, as the 24-105 L IS. It has the classic black matte finish of Sigma professional lenses - very nice, but not very resistant...with time, it shows clearly the wear, in particular if you use it in adverse conditions as high humidity or rain. My biggest complaint about the built quality is the lack of weather sealing; I always use this lens outdoor and it is a bit bothering to know that rain or dust might enter into the lens body. The body of the lens is quite big (visibly bigger than Sigma 10-20 or Canon 17-40) and it has a very peculiar front element, that is protected by the fixed lens hood. The ring closer to the camera body is the zoom ring, while the ring closer to the lens hood is the focus ring: they are a little stiff, but that's OK in this kind of lens, the slight stiffness assures that you don't move the zoom or the focus unintentionally. The lens does not extend during zooming: a nice plus, that partially compensates the lack of weather sealing. Next to the lens mount there is the AF switch. Even though I use almost always this lens in manual focus, it has the excellent Sigma HSM (ultrasonic) AF motor with full time manual focus, that ensures fast and quiet AF. Of course, the lens does not extend durin focussing, nor it rotates the front element: all the focus operation are internal. On the rear of the lens, it is possible to mount Gelatin-tipy filter - they are more awkward than the classic filter, but the exceptional angle of view and the very convex front element of this lens make impossible to use the standard front-type filters. That said, I am not a fan of filters so this is not a big problem for me.

Similar lenses (for Canon EOS)

The Canon 16-35 f/2.8 II is the widest zoom in the Canon lineup. In comparison with the 16-35, the Sigma has many disadvantages: the image quality is no as good; it is 1 stop darker at the wide end and 2 stops darker at the tele end; it is not weather sealed. On the other and, the difference in terms of angle of view is so big that I've choosen the Sigma instead of the professional Canon 16-35; it would be great if Canon annouces a 12-24 f2.8 L lens with weather sealing and brighter aperture, but so far this lens doesn't exist. 

I did not considered the Canon 14mm f/2.8 II: it is still not as wide as the Sigma; it has not the versatility of zoom (that I consider very important for landscapes) and, more important, it is ridiculously overpriced - I'd never pay $ 2,100 for this lens, knowing that Nikon offers an outstanding 14-24 f/2.8 zoom, that is razor sharp even at f/2.8 in the corners, at $ 1,800!

The awesome Nikkor 14-24mm f/2.8 G is the only lens currently in production that comes close to the Sigma 12-24. Until some time ago, it was not possible to mount Nikon G lenses on Canon EOS bodies, but now that the Nikon G - Canon EF adapter is avaibable, you can seriously consider the Nikkor 14-24 even if you have a Canon body. If I had a Nikon D3, I'd buy it in a earthbeat. It is not as wide as the Sigma, but there is not an huge difference as 16mm vs 12mm, and overall it is almost perfect - it is f/2.8, it has first rate image quality and it is weather sealed. With the G-EF adapter, you can use it, but you have to work in stop-down, and you lose autofocus...is it worth it? If you want the absolutely best image quality, yes, it is a better lens than Sigma 12-24 or Canon 16-35 II. 

Image Quality

Remember that you can easily adjust color, distortion, chromatic aberration and vignetting with Photoshop; even though I list every aspect of image quality I don't consider these aspects as important as the other three that can not be corrected with Photoshop (sharpness, contrast and flare). You can enhance a little sharpness and contrast with PS, but the results are not as good as a photo taken with a lens that is sharp and contrasted.

The image quality is really good, considering the low price and the extreme angle of view. That said, keep in mind that there is some sample variation - my first copy was very soft in the corners even at f/16, while this copy is super sharp from corner to corner.

In-depth look: Field of View, the difference between 12, 14 and 16mm

What makes the Sigma 12-24 a truly unique lens is its extreme angle of view. The following image compares the field of view that you get with a 12mm, with a 14mm (as the Nikkor 14-24) and a 16mm (as the Canon 16-35). The difference is huge!

In-depth look: Sharpness

I was really curios to see how the 12mm, the most extreme rectilinear wide-angle currently in production, performs on the high resolution sensor of the 1Ds3. I have photographed a very detailed scene at 12mm with various apertures, and here you can see 100% crop from the 21mp file. The next photo is the test target; the red squares are the crops.

100% crops:

	Center	Corner
f/4.5
f/5.6
f/8
f/11
f/16

I must say that I am really impressed by the sharpness of this lens - there is almost no difference between the center and the corners, and even wide open it is almost as sharp as at f/8 or f/11. Impressive! 

Sample Photo

The following sample show the image quality of the Sigma 12-24 EX DG. The photo has been taken in RAW format and converted with Photoshop CS3; I processed it to optimize the image quality (contrast, color, sharpness), and I saved it as high-quality JPEG for web display. You can download both the processed JPEG and the original, untouched RAW file.

Click on the image to download the full size JPEG sample, or use the RAW link to download the untouched RAW (large file!). Please respect the copyright! This image can be printed only to evaluate the quality of the camera, for personal purposes. All other usages are prohibited.

Winter - Sigma 12-24, ISO 100, 1/13 f/11 [ JPEG / RAW ] - a very detailed landscape photographed at 12mm, with 1Ds3

Other Reviews

Conclusions

Conclusion

The amazing Sigma 12-24 is not a lens for everyone. If you don't have a fullframe camera and you don't plan to buy one soon, there are better choices for APS-C format: on a 450D or 40D the Sigma 10-20 gives a wider view and slightly better image quality. If you have a Canon fullframe camera, instead. the amazing angle of view of the 12-24 makes it very interesting, if you can live without weather sealing and bright aperture. Since there aren't real Canon alternatives, I highly recommed it to landscape photographers (with fullframe cameras) that wants the widest angle of view, but keep in mind that there is some sample variation - if your copy does not performs as well as I showed in this test, I'd recommend to send it back and try another copy.

If you have a Nikon fullframe, instead, I'd suggest the Nikkor 14-24; you trade up some angle, but you get even better image quality, f/2.8 aperture, and better built quality.

Do you have comments or questions?

If you have comments or questions about this article, feel free to ask in the Juza Nature Photography Discussion Forum!