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The Camera Eye
Linda Dextre’
LMS
2009
The First Camera
World Book, 2011
• The Camera Obscura
means "dark chamber"
• The first camera was a
darkened room with a
single small opening.
• Light coming through the
opening projected an
inverted image of a
brightly lit exterior object
onto the opposite wall.
The First Camera
• The ancients used the camera obscura to view
eclipses; later it was useful to artists for
tracing reflected images.
The First Camera
• By the 19th century, lenses and mirrors had been added to correct the
inversion and to project the image onto paper, where it could be easily traced.
•In 1826, J. N. Niepce used a camera obscura to project an image onto lightsensitive paper, creating in effect the first photographic camera.
How a Camera Works
All cameras work on the same principle.
A camera is a chamber sealed to keep out
unwanted light. In fact, the word camera
comes from a Latin term meaning chamber.
Lens
•
When you take a photo or “exposure”, light
from the scene being photographed enters
the camera, usually through a lens.
• The eye lens focuses by thickening or thinning.
Lens
The lens contains one or more curved pieces
of glass or plastic that bends and focuses the
light onto the film or image sensor.
The human eye also has a lens that focuses
and inverts the image onto the retina.
Aperture
The aperture of the camera lens works like the
iris of the eye – it opens and closes to allow
more or less light in.
Pupil
The pupil is the opening in the iris which allows
light to enter the eye. It is the same function as
a camera lens opening.
Retina
• The lens projects an inverted (upside-down)
image of the scene onto the film or sensor.
The eye’s retina also records the inverted
image from the lens.
Cones and Rods
• Cones are color sensitive and absorb strong
light
• Rods are black and white sensitive and absorb
softer light.
Anatomy of the Eye
Eyes and Light
• Human eyes are sensitive to a small portion of
the electromagnetic spectrum that includes
the visible colors -- from the longest visible
wavelengths of light (red) to the shortest
wavelengths (blue).
How Film Works
• Film is layered with an emulsion, composed of
gelatin within which tiny particles of lightsensitive salts have been suspended. The salts
used are usually silver halides, such as silver
iodide.
How Film Works
• The halides, which are
sensitive to light, turn
dark when light strikes
it.
• The more light, the
darker it gets.
• Take a look at the
negative film at your
table to see where the
most light struck the
film.
Creating a Positive Photographic Image
In the developing lab, the film is chemically
processed. It disables the light sensitivity, so
that it can be handled in the light.
The result is a photographic negative. When
light is shone through the negative onto lightsensitive paper, it produces a normal or
positive image.
Now Take a LOOK
• Take a moment to look at the photo
equipment .
• Locate:
– lens
– Aperture
– shutter
– film area
Optical Illusion Fun!
• At your table, gather around the ipad.
• Take turns using the ipad’s Color Uncovered
app.
• Which did you find most interesting?
• Why?
• Jot down your answer on a sticky note and
place it in the exit bin.
List of Resources
• Sobieszek, Robert A. "Camera obscura." World Book
Student. World Book, 2011. Web. 3 Jan. 2011.
• "camera obscura." Grolier Multimedia Encyclopedia.
2009. Grolier Online. 26 Sep. 2009
<http://gme.grolier.com/article?assetid=0049630-0>.
• Adventures in Cybersound; Camera Obscura : Aristotle
to Zahn.
http://www.acmi.net.au/AIC/CAMERA_OBSCURA.html
•
Photo Credits
• http://www.sapdesignguild.org/editions/editi
on9/images/eye_72.gif
• Linda Dextre – Lalito and Light 2009
• MS Office Clipart