Shallow Depth of field help

[JerryPH]

Its a good, sharp and cheap lens. More than worth it's money... but understanding DOF is more important, because you can blur pictures (bokeh) using lenses with smaller apertures as well. Understanding DOF and how it works is the key. I posted THIS in another thread recently.

 

[Dao]

Yes, I took this picture with F/5.6 at the St. Louis Zoo. The focal length is about 210mm. I just need to make sure I have enough room for the background to have the blur effect.