The Camera

Parallax:

the difference between the view of an object as seen through the picture-taking lens of a camera and the view as seen through a separate viewfinder.

Pentaprism:

a prism that has five faces, a pair of which are at 90° to each other. a ray entering one of the pair emerges from the other at an angle of 90° to its original direction: used especially in single-lens reflex cameras to reverse images laterally and reflect them to the viewfinder.

Pellicle:

a thin, partially reflective coating, as on a beam splitter or pellicle mirror.

Viewfinder:
a device on a camera showing the field of view of the lens, used in framing and focusing the picture.

inisde view of single lens reflex camera

Apperture:
An opening, usually circular, that limits the quantity of light that can enter an optical instrument.

Shutter: 
A mechanical device for opening and closing the aperture of a camera lens to expose film or the like.


Exposure:
The total density of light allowed to fall on the photographic medium


Depth of Field:
The range of distances along the axis of an optical instrument, usually a camera lens, through which an object will produce a relatively distinct image.

F-Stop:

The setting of an adjustable lens aperture, as indicated by an f number.

 Focal Length:

The distance of a focus from the surface of the a lens or curved mirror. 

Cannon Rebel T3

 

Buttons on the Camera:

Top Buttons!
Mode Dial:
Rotate this dial to switch among Basic Zone, Creative Zone, and Movie
modes.

Sensor Focal Plane:
 The symbol on the top side of the camera, to the left of the viewfinder, senses and marks the focal plane.

 Flash Accessory

Main Dial:
The dial is used to make many shooting settings.

Shutter release button:
Partially press this button to lock in exposure and focus. Press all the way to take the picture.

On/Off switch:
Flip forward to turn the camera on, and back to turn it off again.

Flash Button 

Back Buttons!
Menu button:
Exits the menu displayed on the rear LCD of the T3.

Display button:
When pressed repeatedly, changes the amount of picture information displayed.

Live View/Movie button:
Press this button, marked with a red dot to its left, to activate/deactivate Live View.

Cross keys:
This array of four-directional keys provides left/right/up/down move-
ment to navigate menus, and is used to cycle among options.

SET button:
Located in the center of the cross key cluster, this button is used to
confirm a selection or activate a feature.

Quick Control/Direct print button:
This button activates the Quick Control screen (described later in this chapter), which allows you to set image recording quality and switch between single shot and self-timer/remote setting.

Aperture value (AV)/Exposure compensation button:
When using manual exposure mode, hold down this button and rotate the Main Dial to specify a lens aperture.

Playback button:
Displays the last picture taken.

AE/FE (Autoexposure/Flash exposure)/Thumbnail Index/Zoom Out button:
This button, which has a * label above it, has several functions, which differ
depending on the AF point and metering mode.

AF point selection/Zoom In button:
In shooting mode, this button activates autofocus point selection. In playback mode,
if you’re viewing a single image, this button zooms in on the image that’s displayed.