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.