<p class="first"]Ihaven't used the Canon versions, but I do own (and love) the Sigma 50 1.4. It originally front focused on my 50D (and then 7D) requiring a +20 MA. I eventually brought my lens and camera to a Sigma repair center. After calibration, my lens is now spot on (there was indeed a needed firmware updatefor the lens).
<p class="first"]This lens issharp wide open with beautiful colors and phenomenal bokeh. Perhaps not as great as the Canon 1.2, but I think superior to the Canon 1.4.
<p class="first"]Indoors, I tend to use my Canon 17-55 the majority of the time for it's versatility. But in dim lighting, even f/2.8 with IS isn't always enough. That's when I switch to my Sigma. Obviously, you have to be careful shooting wide open with such a thin DOF. Now that I think of it, I don't often use the lens for outdoor photography.
<p class="first"]The lens excels at portrait shots, and that's what Iroutinely use it for. Sometimes I do wish I had something a little wider shooting indoors, though. Maybe a 28or 30 mm would do the trick.
<p class="first"]Here are just a couple of samples of the Sigma in action (on a 50D):[img]/resized-image.ashx/__size/1100x0/__key/CommunityServer-Discussions-Components-Files/8/8814.IMG_5F00_9214.JPG[/img][img]/resized-image.ashx/__size/1100x0/__key/CommunityServer-Discussions-Components-Files/8/6330.IMG_5F00_8141.JPG[/img][img]/resized-image.ashx/__size/1100x0/__key/CommunityServer-Discussions-Components-Files/8/3513.IMG_5F00_8099.JPG[/img]
<p class="first"]Oh, and here is a 100% crop of the 1st image:
<p class="first"][img]/resized-image.ashx/__size/1100x0/__key/CommunityServer-Discussions-Components-Files/8/4111.IMG_5F00_9214crop.jpg[/img]