Psychology 3680
Course 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 listserve
following the lectures.
Natural History of Vision
Masks for Squinters
Bartisch 1583
Ibn Al-Haitham ca.1040.
Leonardo daVinci ca. 1500
Des Cartes 1664
Structure of the
Visual System
Peripheral
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
A Small Pupil
Kuppers, 1972, p.25
A Large Pupil
Kuppers, 1972, p.25
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.
.