Scholar born in Basra who studied vision and light through experiment
Plate 031
c. 1011–1021 CE
Cairo, Fatimid Caliphate
No photograph is shown for this exhibition. The museum displays an image only where it can show the object honestly.
About this date
Ibn al-Haytham wrote his Book of Optics while under house arrest in Cairo, between 1011 and 1021. Observations of the image in a dark room are much older.
About credit
The pinhole image was noted by ancient Chinese and Greek writers. Ibn al-Haytham gave the first systematic, experimental account of how it works and of vision.
Chapter II
The world before
Life before the Camera Obscura and Optics
Earlier theories held that the eye sent out rays, or that objects shed copies of themselves. They were argued mostly from philosophy.
II
The human achievement
How it came about
In Cairo, Ibn al-Haytham tested light through small openings and in dark rooms, and described how light travels in straight lines, reflects and refracts. He proposed that vision is caused by light entering the eye. A Latin translation spread his work through medieval Europe.
III
Understanding the invention
How it works
The Camera Obscura and Optics, explained in two steps.
01
Step 01 of 02
Light travels straight
Rays from each point of a bright scene pass through the pinhole and cross, so the image appears flipped.
Light travels straight
A smaller hole is sharper
IV
The transformation
What changed for humanity
Science
Experiment became a model for testing ideas about nature.
Art
Painters used camera obscuras to study perspective.
He argued that experiment could settle questions about nature, and the Book of Optics became a foundation of optics in Europe. The camera obscura led to artists’ aids and, later, photography.
V
Before and after
Life before and after The Camera Obscura and Optics
Before
Debate over rays leaving the eye.
After
Tested descriptions of light entering it.
On larger screens, drag the divider (or use the arrow keys) to give more room to the world before or after.
Later biographers say Ibn al-Haytham had to feign madness to escape a dangerous commission from the caliph and was confined; the details come from sources written long afterwards.
Where accounts differ, this museum follows the documented record and says so.
