Sigma 50 or Canon 50 for sports?

Yea, I know "50 is too short for sports". Actually, I use it a fair amount for under-the-bucket basketball where I actually find it a bit long. So please no recommendations for the 85 f/1.8, 135L, 17-55 f/2.8 or 70-200 f/2.8 - I already have them.

I'm considering swapping my Canon 50 f/1.4 for the Sigma 50 f/1.4. I shoot the Canon at f/2.2 or f/2.5 and find off-center sharpness to be OK but it could use a bit of improvement. I've heard the Sigma is sharper than the Canon below f/2.8 but I'm wondering about it's focus accuracy.

Are any of you using the Siggy for basketball? Anything to report?

My first game is tonight. I'll be using the 85 and 50 as usual, but thinking about the Sigma.

Never heard a Sigma was sharper than a Canon at lower f/stop - in fact only heard the exact opposite, but that was for other lenses and not the 50. My 50 is sharp as can get, though when I first bought it used it wasn't - had to send it in to CPS to get fixed.

Stop thinking about it. Any difference will be so minimal you might notice it in a studio setup but not sports. Also as Mike said I've only heard the opposite to be true.

I actually use my 50 1.2 for volleyball all the time. I've not had any experience with the 1.4, but I'd say try them both if you can, and compare focus speed, I think thats where you would tell the biggest difference, which is important for sports.

Who says the Sigma is better? Speaking of the Canon 50 f/1.4, DP Review says "Sigma's new young pretender can outmuscle it comprehensively at wider apertures". Their sharpness graphs show quite a difference at f/2, where I use the lens most of the time.

BUT, my concern is about focus accuracy and speed. Canon's lens isn't the best but from what I've gathered, the Sigma isn't really top-notch either.

As liam5100 said, I may have to just get one and try it side by side to see which one meets my needs best.

As a rule, the Sigma is sharper wide open (there aren't too many sharp EF 50mm at f/1.4), but it's a fraction slower to focus than the EF 50mm f/1.4, despite its ring HSM vs. the micro USM in the Canon. The huge glass in the Sigma really puts pressure on the HSM motor.

Shot 4 games today .. High School ... with the nifty 50 ... and no problems .. these teams all drive to the basket and I got all of the shots I needed. I also shoot with a 70-200 2.8 IS .. and it is a fine lens but heavy after a couple of games .. shoulder aches. Next lens is the 24-70 2.8 .... could have used the wide angle today.. would have been nice.