Originally Posted by hyogen
...My thought for this 30mm f/1.4 was for more clear shots and much more blurry backgrounds. Whether I take portraits or pictures of audio gear or other toys indoors or even outdoor shots...
I've always loved the standard 50mm f/1.4 thing, and when I picked up my first DSLR (a crop sensor Canon), I wanted to get as close to 50mm f/1.4 as I could. The Sigma 30mm f/1.4 was as close as I saw (48mm equivalent).
I think you'll be able to get the blur (bokeh) you want with it. Here are some shots from when I first picked it up (I'm not presenting these as examples of high artistry, but as examples of blurred background):
I later switched to Nikon, but loved the 30mm f/1.4 so much that it was one of the first lenses I picked up for Nikon, too. The following two shots were just test shots I took to test focus (both my Canon and Nikon 30mm f/1.4 Sigmas focused well), and the first photo shows some background and foreground blur.
f/1.4 (Nikon version of Sigma 30mm f/1.4)
f/2.2 (Nikon version of Sigma 30mm f/1.4)
And sometimes, in real life, the big aperture comes in handy. A whole bunch of us went on a fall camping trip some years ago, and I took this photo (again with the Nikon mount version):
f/1.8 (Nikon version of Sigma 30mm f/1.4)
The only light was from the fire and embers (and that glow-in-the-dark necklace around the girl's neck). I tried using an f/2.8 lens, but it just didn't work in that little light--it was very dark outside of that fire, as we were well away from any city lights. (I know it's noisy, but I'll take that over what a flash would've done to that shot.)
So, again, I don't expect my photos to convince you, but I love shooting with that lens. It might be safe to say I had more fun with that lens on two different Canons, and then a Nikon D300, than any other lens.
Now that I moved to a full-frame sensor, I picked up a Nikon 50mm f/1.4G lens. Also, the increased high-ISO ability of the newer full-frame camera (relative to my previous cameras) does allow me to use f/2.8 when I'd previously have to turn to the f/1.4.