Transcript Properties of Lenses - Seton Hall University

Properties of Lenses
Dr. Kenneth Hoffman
Focal Length
The distance from the optical center of a
lens to the film plane (imaging chip) when
the lens is focused at infinity.
Normal Lens
A lens whose focal length is approximately
the diagonal of the size of the format being
used, e.g., 50mm for 35mm film, 25mm for
16mm film.
Normal Lens
Wide Angle Lens
Any lens of relatively short focal length. Has
a wider angle of view and therefore shows
much more of the action. Distance
between objects is exaggerated. Greater
depth of field.
Wide Angle Lens
Telephoto Lens
A lens of greater than normal focal length
with a narrow angle of view. Objects
appear to be compressed in distance
between them. Shallow depth of field.
Telephoto Lens
Dept of Field
The distance in front of a camera and its
lens in which objects are in sharp focus.
Depth of field is influenced by:
1. Focal length of lens
2. Subject-to-camera distance
3. f-Stop
4. Shutter speed
Shallow Dept of Field
Extended Dept of Field