just want to know how does one compute depth of field at a given aperture, focal length, and distance from subject??


this is coz i just shot some portrait pictures... used a 5D2 and a 24-70 2.8L .... distance was about 3-4 feet from subject focal length on lens was about 70 and opening was 2.8.... was surprised to some OOF blur on some parts of the subjects body .... focus point was the face i.e. eyes, nose.....


thanks