Psychology 3680Course Website
http://www.psych.uleth.ca/Courses/Spring%202004/3680/3680.htm
Or
http://www.psych.uleth.ca
And follow the links….
Relevant URLs
Byron will send relevant URLs to the course listservefollowing the lectures.
Natural History of Vision
Masks for SquintersBartisch 1583
Ibn Al-Haitham ca.1040.
Leonardo daVinci ca. 1500
Des Cartes 1664
Peripheral Visual System
Structure of the Visual System
Parts of the eye
Pinhole Camera
Camera Obscura
Diverging• Reflected light goes in all directions• From each point on object• Only very small part passes into camera obscura• At infinity rays are parallel
Kuppers, 1972, p.25
A Small Pupil
Kuppers, 1972, p.25
A Large Pupil
.
Functions of the Pupil• Lens gathers light• Lens also create problems
– Spherical Aberration– Limited depth of Field
• Iris/Pupil is used to change the trade-off.– Bright -> smaller for better optics– Dim -> optimize for more light gathering
.
Spherical Aberration• Different parts of lens converge to different
focal points.
.
Spherical Aberration• Reduced by small pupils: clearer vision
Depth of Field
The smaller the pupil, the larger the range of depths over which objects
will be in focus.
.
Pinhole Camera
• Objects at different distances will be in focus. Infinite depth of field.
• Image plane of film is not critical for focus.
.
Large Lens • Objects at different distances will be in
focus at different distances behind lens
• Narrow depth of field.