I have used Sigma lenses on and off in the last 6 or 7 years. The 28-70mm f2.8, bad lens, possibly due to copy variance, as Sigma is famous for that. 20mm f1.8, very good lens, when it focused. I still have a 15-30mm f3.5-4.5. In fact, I have had it for about 3 years now. It's relatively cheap for the wide angle it provides. Excellent on 1.5x or 1.6x crop cameras, but the far edges are a bit soft on full frame.
When the 50mm f1.4 EX lens came out, I was intrigued by its radical design. This is probably the only 50mm f1.4 lens ever made with a 77mm filter size. Even the 50mm f1.2L lens I have, its filter size is only 72mm. The Canon 50mm f1.2L is heavier though.
Side by Side, Sigma 50mm f1.4, Canon 50mm f1.2L, Canon 50mm f1.4. Click on picture to see a larger version.
Took a few pictures with the Sigma today. Very impressed with its sharpness. It focuses perfectly on my 5D without any issues. Sigma EX lenses come with 10 year warranty, which should be a relieve in case of future compatibility issues.
One issue I have with the Sigma lens is the lens hood. It's way too loose. Maybe the hood I got is not the original hood made for this lens, as the lens I bought was an open-box one. The hood is too easily moved and could cause vignetting if not aligned properly.
Will be interesting to test this lens against the Canon 50mm f1.2L.
William with is Rubik's Magic. He can solve it under 3 seconds now -- 5D & Sigma 50mm f1.4 EX @ f1.4. Larger Picture.
Megan practicing piano -- 5D & Sigma 50mm f1.4 @ f1.4. Larger Picture.