|A camera is a
machine that records a picture. With film cameras, the picture is recorded on film. With
digital cameras, the image is recorded on something called a charge couple device. Motion
picture cameras have film, which is kept moving with a tiny motor.
Cameras work on the same basic principles. Cameras are made up of a
light-proof box with film inside and a lens at the front. There is an adjustable hole, or
aperture, where light enters the box and is focused. There is a shutter that controls how
far the lens opens and for how long; a track or motor for moving the film after a picture
is taken; and a viewfinder that shows the photographer what the lens sees.
The lens most of the time is glass, but it can also be
plastic or any transparent disk. A lens refracts, or bends light. Light passes through the
lens, and the light is bent to a common point, or focus. A lens also has a set focal
length, where the light will always come to the same focusing point. That point is where
the object youre taking a picture of looks clear and sharp "in
When you open the shutter by pushing a button on top of
the camera, light goes through the lens and hits the film. The film reacts chemically to
the light and is "impressed" with the image you took a picture of. When you have
your film developed, the latent image on the film is brought out and made into pictures.
A digital camera is where the camera is
"married" to the computer. The digital camera works the same way as a film
camera, except when light enters the lens, instead of imprinting on film, the image is
collected as tiny dots of light and color called pixels. Pixels are recorded on a computer
chip called a charge couple device. Each image can be made up of more than a million
pixels. The digital camera stores each image on a small disc drive. When you are done
taking pictures or when the disc is full, you can hook a digital camera up to a computer
and download the images.
A motion picture camera and camcorder are similar types of
cameras. They come in many sizes, from the small ones that almost fit completely into your
dads hand to the big ones Hollywood directors use. Film goes through the camera but
stops quickly to expose, or imprint images on, each frame. Frames go through a camera very
fast, at 18 or 24 frames a second. The shutter spins open and close as you "roll the
film." A little metal thing called a claw hooks into holes on the films edges,
pulls the film into place, retracts while the frame is exposed, and does the same thing
all over again for the next frame. All this is powered by a tiny electric motor.
Click above to see a drawing of a digital camera.
Click above to see a camera's parts.
Click above to see how light enters through the lens. The
lens brings the image into focus onto the film. The aperture regulates how much light
enters the camera. The shutter controls how long the light that comes in through the lens
and aperture falls onto the film. The film receives the image and records it.
Click above to a reel of movie film, divided into frames.