We all know that depth of field can be controlled by aperture and lens focal length, and people spend large sums of money to get a faster and longer lens. However, one of the often overlooked, and thus unused variable to control depth of field often goes unnoticed. Did you know that you can control depth of field just by getting closer or further away from your subject? Try it!
Take a few steps closer to your subject, and the depth of field becomes shallow. Take a few steps away, and when you focus now, the depth of field increases. Of course this will effect your composition, but given the fact that common subjects such as portraits turn out better with tight compositions, chances are that reducing subject distance will give you an overall better picture in any case.