Welcome to the online DOF calculator. With this calculator you can calculate the Depth Of Field (DOF) for any camera/lens combination and a given distance to the subject. Configure the type of camera you have, enter the focal length of your lens, the aperture you wish to set and the distance to the subject. The calculator will then calculate the DOF for you in that particular situation.
Just play around with it; It will give you quite some insight by just trying several values for your different lenses!