Skier

I took this shot to hone my full length portrait skills. One Canon Speedlite 580 II through a 80x80cm softbox from high above and on camera right directed down towards toes. And Nissin Di622 bounced from the ceiling for fill. I don't think I'm needing another softbox stacked below the main light for additional light for the legs. That 80x80cm softbox seems big enough.

Any recommendations for a 50mm EF lens? I don't think my Canon plastic jar of 1.8 II is sharp enough from corner to corner. Any thoughts on Canon 1.4 v Sigma 1.4? Any focusing issues with the latter?