The Camera

Single Lens Reflex Camera 

Optical Path- The path that light takes in traversing an optical system is often called the optical path. The physical length of an optical device can be reduced to less than the length of the optical path by using folded optics

Reflex Mirror- A mirror that, when the shutter is closed, directs light from the lens into the viewfinder instead of onto the image sensor; when the shutter opens, this mirror is raised out of the optical path, allowing light from the lens to fall on the image sensor

Pentaprism- 5 sided reflective prism that is used to separate a beam of light by a constant 90 degrees, even when the entry beam is not at 90 degrees to the prism.

Interchangeable Lenses- Lenses designed to be easily attached to and detached from a camera.

Aperture- The size of the opening in a lens when the picture is taken.

Shutter- A device that allows light to pass for a period of time to expose a photographic film, or to a light-sensitive electronic sensor to light, to capture a permanent image in a scene. 

Exposure- The total amount go f light that is able to fall into a photographic medium when a picture is being taken.

Depth of field- The amount of distance between the nearest and farthest objects on focus.

F-stop- The ratio of the focal length of the lens, to the diameter of the aperture. When a lens is set on the smallest f-stop, it is said that is is "wide open".

Focal length- the measure of how strongly a system focuses or defocuses light. 

Canon Rebel T3

• Mode dial
• Power switch 
• Flash button
• Main dial
• Shutter button