Originally posted by interested_observer [*]Focal Length - Generally wide angle lenses (shorter focal lengths) have deep depth of field, while telephoto focal lengths (longer) exhibit the shallower depth of field.
Well, it isn't that dependent of focal length, it's mainly about magnification. At the same magnification things get really close except extremely wide lenses that you have to count in another aspect (can't remember the name of it). So at 1:1 macro distances it's almost the same, though compressing the background gives an illusion of deeper DOF.
Understanding Depth of Field in Photography
"If the subject occupies the same fraction of the image (constant magnification) for both a telephoto and a wide angle lens, the total depth of field is virtually* constant with focal length! This would of course require you to either get much closer with a wide angle lens or much further with a telephoto lens"