M.O.D.
The M.O.D. (minimum object distance) is the closest distance from the vertex of the front lens to the nearest object at which an image can be focused.
CS and C Mount
The CS-mount lens has the flange back distance of 12.5mm. The C-mount lens has the flange distance of 17.5mm. The CS mount lens is only applicable to the CS mount camera, but the C mount lens is fit for both C mount and CS mount cameras as long as a 5mm adapter ring is used to match the CS mount camera.
Depth of Field
The depth of field (DOF) refers to the area within the field of view which is in focus. A large depth of field means that a large percentage of the field of view is in focus. A small depth of field means only a small section of the field of view is in focus. The depth of field is of following properties:
1) The larger the F No. is, the wider the depth of field becomes.
2) The shorter the focal length is, the wider the depth of field becomes.
3) The longer the distance to the object is, the wider the depth of field becomes.
4) The backward depth of field is wider than the forward depth of field.