Originally posted by Shadus
If you are refering to making a picture 'soft', then Kho King mentioned that lens and Canon have one as well, but they can it a 'Soft Focus' lens.
However, most people will just use a soft filter.
Please note that be it soft focus, defocus, soft filter -> it does not only make the background blur, it makes the entired picture soft. The intention is to give it a dreamy, romantic feel to the picture.