I haven't been doing a lot of macro photography lately, as I am hosting a national meeting next week at work (don't ever let yourself get shamed into doing that!) which is keeping me pretty busy, and in what little time I have, I am playing around with a new lens, a Sigma 12-24mm....Yep, you read it right, 12mm at the wide end. And it is a full frame lens! I bought this because I am hoping to be able to do some photography in some ruins early next year and I want something ultra wide that will fit on my full frame dslr. There's nothing wider than this one except fisheyes! And I've always been sort of intrigued by ultrawide lenses and fisheyes, though I know they are really really tough to use.
I'm actually pretty impressed with the lens. It is respectably sharp if you stop down quite a lot (enough that diffraction comes into play, such as f/16 or even f/22). Oddly, it seems sharper at the 12mm end than at the 24mm end, which is not what I expected at all! I've read that Sigma can often improve these things significantly if you send it into them to be serviced, and I'm going to do so with mine in hopes of improving the 24mm end.
The lens is bulky, and certainly not light, but I don't think of it as particularly heavy. One thing I dislike about it compared to the 14mm Sigma prime that I had as a previous ultrawide is that the minimum focus distance is much longer--About 18 inches, twice that of the 14mm. But the 14mm looked like the photos were shot through coke bottle glass on my 1Ds, whereas the zoom gives me photos that I'm quite content with.
Not really relevant to macro, but I thought it was interesting if anyone was looking for such a lens, and some of the perspectives you get at 12mm are wild. Such as the one above, which has no merit at all except that it looks like it was taken from an airplane! (was actually grabbed from a balcony in a moderately high building). You can see the same view from the same spot at a more sane focal length here:
http://www.photomacrography.net/forum/v ... .php?t=250
