To match the depth of field of the human eye, you not only have to take into account the aperture size (which is easily duplicated with just about any lens in any format) you have to account for the relative distance your subject is from the film in film-format-diagonals. So, you can stop a 300mm lens on an 8x10 camera down to 4.5mm but, for objects closer than 10 feet or so, you will have somewhat less depth of field with the 8x10 camera at 4.5mm aperture than your eye at 4.5mm aperture. (http://www.bobwheeler.com/photo/ViewCam.pdf section 9.6 covers this indirectly)

Also remember the eye functions kind of like a 'scan back' in that there is one narrow-angle-of-view (fovea) that scans around the scene, giving the impression of a large field of view.