THE CAMERA

Image capture: Traditional cameras used it to capture light onto photographic film or photographic plate.

Lens: The Lens of a camera captures the light from the subject and brings it to a focus on the film or detector.

Focus: It helps objects within a limited range of distances reproduce clearly.

Complexities: is a medium format that SLR cameras use a hybrid solution.

aperture
shutter
exposure
depth of field
F-stop
focal length

The buttons on the back of a Canon Rebel T3 are:

There's a view finder, a aperture/exposure compensation/ erase button all in one button.

there's also a live view/movie record button, a AE lock and a AF point selection.

There's also a quick control button, a ISO button a menu button a drive mode button, white balance button , AF mode, a Play back button a display button and a speaker.

In a view finder you can see the picture you're about to take.
an aperture/exposure compensation/erase button helps you widen the lens size, let an amount of light in the lens, also it evaluates the light in a photo and that button can erase pictures and videos.
The live view/movie record button lets you see what you're looking and or what you're filming on a bigger screen.
The AE lock and AF point help with automatic exposure lock and auto focus.
The quick control button allows you to control how you take a picture.
an ISO button helps with the measure of film "speed" or sensor sensitivity.
the menu button takes you automatically to the menu.
The drive mode button lets you take multiple pictures at one time.
the white balance button lets you chose the amount of light you would want.
The AF mode controls the auto focus on the camera.
the play back button allows you to see previous pictures or videos you have taken.
a display button only shows the last picture you took.
and a speaker allows you to hear if a video has sound.