lens auto focus when using MFT adaptor on e-pl2?

Hi,

Does anyone know whether auto focus works with a say sigma 50mm f1.4 lens using a MFT adaptor on the e-pl2.

I assume the Panasonic 20mm f1.8 has auto focus since it is recommended a fair bit on this website - but can anyone confirm?

Also told that 20mm doesn't give enough depth and that 50mm is better - thoughts?

Thanks

L