I personally own the Sigma, but I'm using it on full-frame. I needed a micro-focus adjustment for front-focussing. The Sigma is known for focus issues unfortunately. I only had front-focussing which was consistent and therefor good to deal with.


It's absolutely better wide open than the Canon 1.4. I really like it wide open. If you have the opportunity to test or if you've got an easy return-policy, the Sigma is definitely worth a try. I my opinion it's much better than the Canon 1.4


The Canon 1.2 is a whole other story though. I don't have experience with it. Hope you can do something with this.


Jan