Achieving Shallow Depth Of Field with NX5U

I shoot corporate videos (primarily talking heads in small spaces {conference rooms}) with Sony's NX5U and have not been able to achieve shallow depth of field. This is very frustrating as I see more and more people using the Canon 5D and getting amazing looking video, but I am stuck with this camera, so if anyone has had any success in doing this with the NX5U I would very much appreciate your insights. The more specific you can be the better. As always, thanks.

Andrew