""Great lens for the money. Use it indoors with my 50mm (F1.4), mainly at F2 to F2.8 w/ no flash. Pictures are just surprising. Shooting moving subjects at F1.8 indoors will result in blurry / not focused results as expected with the very thin DOF. F1.8 will require some PP to improve sharpness but results are useable.""

    "Let me start by saying I'm not a hardcore fan of any particular brand. I like to gauge lenses by their individual merits, rather than discussing them as a brand.

The Sigma 28mm f/1.8 EX is an excellent lens from an optical standpoint. On digital and film SLRs from Nikon, I was always quite impressed with the optical quality. Even wide-open at f/1.8, it is roughly as good as the Nikkor 50mm f/1.8, which is somewhat low in contrast, but still resolves quite a bit of detail on the focal plane. Stopping down a stop or two, like with most lenses, really brings out the contrast and sharpness, and this lens delivered quite wonderfully, matching the famous 28/2.8 AIS Nikkor for sharpness both up-close and at infinity. Further, this lens allows closer focusing than the Nikkor, and possesses less apparent geometric distortion. As much as I love the AIS28, the Sigma is quite brilliant too.

While very good at infinity, the lens shines for moderate closeups of objects like flowers. Although it says "macro" in the name, it only approaches 1:2.9 magnification, and the distance from the front element is quite small, so live insect photography will likely not be its forte. At this range, the lens also has a much smoother out-of-focus rendering wide-open than much of its competition (such as the 28/2 AIS Nikkor). If you like smooth boke (not everyone does, but many do), this can be a good lens for that effect.

The biggest downsides are the size and the autofocus. Although it is high quality, the lens was simply too big for my taste. Compared to my 28/2.8 AIS, the Sigma is simply massive. In fact, it is about the same size as a 28/1.4 Nikkor, and uses larger (77mm) filters! This is a concern for people who like using filters like polarizers, which get much more expensive at large sizes. The second major issue is that the autofocus mechanism has proven unreliable, particularly on Canon versions of the lens. My Nikon experienced some focus inconsistency at midrange distances (better consistency up close). As I tend to manually focus, this was not too much of a problem, but for those who do depend on it heavily...this lens might cause frustration. Bear in mind, this is not the case for EVERY lens of this make; it is likely an issue with sample variation which has been pointed out for some time. Some people have great luck, some are not so lucky.

As I prefer to manually focus and personally prefer smaller lenses, I opted instead for my AIS Nikkor, which has roughly equal optical quality in a much smaller package with inexpensive 52mm filters. However, I do miss my 28/1.8 Sigma and, were it a smaller, manual focus lens, I would likely be using it today.

If you can get over the gargantuan size and if you can circumnavigate the sample-variation-related AF quirks, this lens is quite beautiful. I must give the designers kudos, even if it's not the perfect lens for me personally."