Chapter 6 binoculars:cameras Flashcards
what are binoculars?
binoculars are two refracting telescopes mounted side by side.
If binoculars are two telescopes, why are they so small?
to make them shorter, binoculars have prisms inside that reflect the light.
why do binoculars have prisms inside?
Prisms act like plane mirrors reflecting light back and forth rather than traveling up a tube
What is the purpose of the thumbscrew on binoculars?
the thumbscrew changes the focal length in order to focus on different objects/distances
How does a digital camera work?
a camera gathers and bends light with a convex lens, and sends the light to a light detector to record the image
What is the shutter?
the shutter is an opening that opens to allow light to enter for a specific length of time.
What is the aperture?
the aperture is an opening through which light travels
After the aperture, where does light go?
light goes though the lens after the aperture
What does the lens do?
the lens focusses the image.
What does the final image look like?
it is inverted, just like in the eye due to the convex lens
What is a wide angle lens?
A wide angle lens has a short focal length, but has a wide field of view. They are short as the lens needs to be near the light detector inside the camera.Closer objects are more in focus
What is a telephoto lens?
A telephoto lens brings far objects into closer view.They are long and increase the distance between the lens and the light detector inside the camer.
Compare eye to camera: Lens Cap
eye lid – protects the eye from damage
Compare eye to camera: Diaphragm
Iris – makes the hole for light to come through bigger or smaller
Compare eye to camera: Lens
in a camera the lens moves closer or away from the light detector, in the eye the lens is changed by the muscles
