When I saw that Sigma was going to be releasing an updated version of their 12-24mm lens, I was quite excited. As a long-time owner of the original version, I had found many creative uses for it, both for commercial work and my own art. There were, of course, the nagging issues about the lens being a bit on the soft side (especially in the corners), but on the whole, I felt those issues were exaggerated by folks accustomed to the type of sharpness delivered by more “mainstream” lenses. After all, the 12-24 was literally without equal as the only rectilinear full frame DSLR lens at the 12mm focal length. When it comes to using it in the real world, the lens does its job well and it can make images that no other lens can.
Don’t get me wrong, the original 12-24mm was not a lens I would want to take with me on a landscape shoot where I would want everything sharp corner to corner. But where I did find it especially useful was for urban and architectural photography. The fact that the lens shows almost no noticeable geometric distortions was a bonus and an impressive feat for any zoom lens, not to mention an ultrawide zoom lens.
So, I lived with the lens’ limitations, used it judiciously, and the lens more than paid for itself. In short, I was happy with it.
But, when the new Sigma 12-24mm f/4.5-5.6 EX DG HSM II hit the scene, well, I could hardly wait to try it out on my 5DII and see if any of the shortcomings of the previous version had been addressed.
The Big Question
Is it sharper? Bluntly, yes. The lens is sharper. Most notably, it is sharper in the corners and sharper at wider apertures.
The most significant improvement is around the edges of the frame, where the old version did tend to smear details. The new one does a much better job here. No, the most extreme edges of the corners still will still not be razor sharp….but for a zoom that goes down to 12mm I think they are not too shabby. Given the fact that those corners make up such a small portion of the overall area of the scene (particularly at the widest focal lengths) I don’t feel there is a lot to complain about here.
The performance at wider apertures is without a doubt much more impressive. With the old version, I felt like it really needed to be stopped down to get the most out of it, and so almost never shot it wide open. It was just one of those things I knew was an inherent weakness of the lens and lived with it. But now, shooting at f/4.5 or f/5.6 is a viable option.
When stopped down, improvements in center sharpness are less dramatic. They are there, but you really have to zoom in to 100% on screen to see it.
The Other Improvements
Vignetting is improved. I never noticed it much on the older version (other than wide open where it was extremely prominent). But comparing the two side by side, the difference is readily apparent.
Chromatic aberration is held in check very well. The old version of the lens did have some issues with purple fringing occasionally, although I wouldn’t say it was horrible. But on the new version, I had a hard time finding any at all.
Lens flare is also well controlled. The new version seems less prone to flaring and retains better contrast even when shooting towards the sun. And when you’re shooting at 12mm, it’s not hard to be shooting towards the sun.
Finally, I feel there’s something about the way the new lens renders colors. Somehow, they just seem cleaner, for lack of a better term. The new lens uses Sigma’s “FLD” glass, which is the company’s equivalent of fluorite, and so it could be the result of better light transmission across the spectrum than the old lens is producing. Or it could be that the marketing hype has gotten into my brain. Either way, I feel that with new version, colors have just a bit more pop and clarity.
So, overall I was very impressed with the image quality. But there was one issue that immediately jumped out at me as a weakness compared to the old lens: geometric distortions. Whereas the old lens was well corrected and exhibited barely noticeable barrel distortion, the new version shows a very prominent “hump” at wider focal lengths. Upon inspection, it’s actually a rather complex distortion. If we take a horizontally oriented images as an example, there is a clear bowing effect visible towards the top and bottom of the image. This bowing flattens out at its far edges, reminding me of so-called “gullwing” distortion (although it doesn’t flare upwards quite as much at its ends). But the other strange characteristic is that the center of the image actually shows a very mild pincushion effect.
As an architectural photographer with an obsession for straight lines, this stressed me out quite a bit. There was no way to completely correct for this in Photoshop. If you applied barrel correction to make the hump on the top of the image flatten out, you were left with pincushioning in the center of the image, and the far edges would flare out in gullwing fashion. And to add to the problem, doing this smeared the details slightly as well, minimizing the resolution gains of the new lens over the old lens.
In my desperation, I turned to Tom Niemann and PTLens for help. Now, of course I’ve know about PTLens for many years, I just never really had much use for it as most of the lenses I used were already fairly well corrected. I also dreaded having to wait to get the lens calibration performed to see if this distortion actually could be fixed without significantly degrading the image quality. I started thinking that maybe it would just be easier to return the new lens and live with the old one. But, much to my surprise, I received an email back from Tom within about a half hour of my initial inquiry. And after I sent him a set of photos for calibration, his response was again amazingly fast.
All was not well, however. While PTLens did manage to correct the image a little better than Photoshop, the pincushioning in the center of the image remained. I was starting to lose hope, but I emailed Tom again, asking if this was something beyond PTLens’ ability to fix. Well, in less than an hour’s time, Tom had the problem licked. The issue, he informed me, was that he needed to apply a third coefficient to the correction…apparently this is the first time he had to use three coefficients for a lens correction. (See, I told you this distortion was complex!)
The end results, though, are excellent. PTLens is indeed able to make all the lines straight (or at least straight enough not to bother me). What’s more, I was pleasantly surprised to find that there is barely any impact on resolution. A much better performance than Photoshop.
The Happy Ending
So, with all-around improvements in image quality, and with PTLens rescuing the distortions, I am able to keep this lens without any reservations. I should add that while the geometric distortions are quite obvious when shooting architecture or subjects with long straight lines, they are not that noticeable otherwise. So using PTLens isn’t necessarily a forgone conclusion with this lens…but it is something I would strongly urge prospective owners to keep in mind. After all, if you are going to shell out almost a grand for a lens, what’s another $25 for PTLens?
Which does brings us to the subject of cost. As you’ve no doubt noticed, this lens is not cheap. So is it worth the asking price? Well, as with most things, that depends on you, your needs, and your wants. The first question of course would be do you really need/want an ultrawide angle lens? If you own a crop sensor camera and want to go ultrawide, there might be a few better options out there. If you’re in the full frame arena, there are a couple of 14mm prime lenses as alternatives (the much more expensive Canon and the much cheaper Samyang). But as of yet, there’s still no other rectilinear as wide as 12mm. (Other than Sigma’s first version of this lens, of course….which at the moment is still comparatively pricey at most stores.)
As far as I’m concerned, the Sigma 12-24mm II stands on its own merits quite well. It does what pretty much no other lens can claim to do, and the image quality it delivers is quite impressive given the extreme optics.
In closing, here a few more images I snapped in my initial days evaluating this lens. (No post processing was applied to the images other than opening in Adobe Camera Raw and applying slight exposure compensations if necessary; all other settings remained at default.)