Fiber Optics

Fiber optics (optical fibers) are long, thin strands of very pure glass about the diameter of a human hair. They are arranged in bundles called optical cables and used to transmit light signals over long distances.

Parts of a single optical fiber
If you look closely at a single optical fiber, you will see that it has the following parts:
Core - Thin glass center of the fiber where the light travels
Cladding - Outer optical material surrounding the core that reflects the light back into the core
Buffer coating - Plastic coating that protects the fiber from damage and moisture Hundreds or thousands of these optical fibers are arranged in bundles in optical cables. The bundles are protected by the cable's outer covering, called a jacket.

Parts of the camera

Lens - It draws the light into the camera and focuses it on the film plane.

Shutter - It open and closes to control the length of time light strikes the film. There are two types of shutters: a leaf shutter, located between or just behind the lens elements, and a focal plane shutter, located in front of the film plane.

Shutter Release - The button that releases or "trips" the shutter mechanism.

Film Advance Lever or Knob - It transports the film from one frame to the next on the roll of film.

Aperture - It dilates and contracts to control the diameter of the hole that the light passes though, to let in more or less light. It is controlled by the f-stop ring.

Viewfinder - The "window" through which you look to frame your picture.

Film Rewind Knob-This knob rewinds the film back into the film cassette.

Camera Body - The casing of the camera which holds the encloses the camera pats.

Flash Shoe - This is the point at which the flash or flash cube is mounted or attached.

Self-Timer - This mechanism trips the shutter after a short delay - usually 7 to 10 seconds - allowing everyone to be in the photograph.

Shutter Speed Control - This know controls the length of time the shutter remains open. Typical shutter speeds are measured in fractions of a second, such as: 1/30 1/60 1/125 1/250 1/500 and 1/1000 of a second.

Ray diagram for diverging lens

location: beyond 2f

Ray diagram for converging lens

location: at f

location: between f and v

location: at 2f, between f and 2f

location: beyond 2f

Ray diagram for convex mirror

location: in front of the mirror

Ray diagram for concave mirror

location: at f

location: between f and v

loacation: at c, between c and f

location: beyond c

Parts of the eye

The Eye
The eye is like a camera. Light comes in through the cornea, a clear cover that is like the glass of a camera's aperture. The amount of light coming in is controlled by the pupil, an opening that opens and closes a little like a camera shutter. The light focuses on the retina, a series of light-sensitive cells lining the back of the eye. The retina acts like camera film, reacting to the incoming light and sending a record of it via the optic nerve to the brain.


Other parts of the eye support the main activity of sight: Some carry fluids (such as tears and blood) to lubricate or nourish the eye. Others are muscles that allow the eye to move. Some parts protect the eye from injury (such as the lids and the epithelium of the cornea). And some are messengers, sending sensory information to the brain (such as the pain-sensing nerves in the cornea and the optic nerve behind the retina).