Sigma Zoom Super Wide Angle 12-24mm f/4.5-5.6 EX Aspherical DG Autofocus Lens for Pentax AF

Comments about Sigma 12-24mm f/4.5-5.6 AF Lens:

I've had this lens since February 2005, shortly after it came out, and before Pentax announced their 12-24. Though the Pentax 12-24 certainly has its advantages, I'm very happy with this lens and have no plans to replace it with the Pentax.

I mostly use this lens for hiking, and for family gatherings such as birthdays & holidays.

As wide as it is on APS-C digital cameras, it's even wider on 35mm film cameras (it completely covers the 35mm film frame, unlike the Pentax 12-24), and of course full-frame digital cameras if Pentax ever makes one.

The 122 (one hundred and twenty two!) degree field of view (diagonal) on 35mm film is loads of fun. I once stood up on a chair in a living room during a birthday party and aimed straight down. I got everybody in the room in that shot, from one side of the room to the other! And I mean I got the whole person of everyone, not just feet. It's so wide, people often have no idea they're in the shot!

To get the same field of view on APS-C digital without going to a fish-eye lens, you'd need an 8mm non-fisheye. Good luck with that!

I hike with this lens often and it is not particularly heavy.

Another thing I like about this lens is that if one of the kids does something cute, 24mm on APS-C, equivalent to 36mm on 35mm film, is close enough to the wide end of normal to take normal family snaps, so when hiking I don't have to switch back and forth between this lens and a normal lens. Often this is the only lens I use the whole hike, even if I take other lenses along.

Another thing I like is that for all practical purposes there is no distortion! Look at the distortion pictures in the formal reviews -- distortion is incredibly well controlled for such a wide lens.

I've never noticed any CA, though I don't do much pixel-peeping. It may be that there is a small amount of CA that I just haven't noticed.

One important thing to note about this lens is that it is soft wide open, but those shots sharpen up very well in post-processing (the softness is due to low contrast, not low resolution). So if you never do any post-processing, you might find this lens unacceptably soft unless stopped down a stop or two. But if you are familiar with sharpening pictures in post-processing, especially with unsharp mask, this lens is sharp even wide open. This softness without post-processing is the reason for 4 stars instead of 5.

The build quality is very good for a mostly plastic lens. It's very tight; nothing is loose. The mount and built-in hood are metal. I'd say it's build quality is a bit nicer than my Pentax FA lenses, and about as nice overall as my DA 16-45 lens. I assume it doesn't measure up to a DA* in build quality.


The downsides:

The zoom ring is stiff.

Filters on the front vignette, even thin filters, and even on APS-C. Even if you just slide on the attachment that allows it to accept filters (it also is what accepts the lens cap), with no filters on it, it still vignettes slightly. Of course, on 35mm film, it vignette a lot more.

Like any lens this wide, flare is an issue if the sun is in or near the frame. Occasionally a series of small flares in a shot can create a pleasing affect, but for the most part shooting into the sun should be avoided with this lens.


Overall this is one of my favorite lenses. It's a lot of fun, and I love the results.