The Language: Pixel: The smallest unit of a digital image that can be represented or controlled.
Megapixel: One million pixels gridded into a pattern in the shape of a rectangle.
Resolution: The number of pixels that make up an image. An image that is 2048 pixels in width and 1536 pixels in height has a total of 2048×1536 = 3,145,728 pixels or 3.1 megapixels. One could refer to it as 2048 by 1536 or a 3.1-megapixel image.
The Theory: Aperture: Diaphramatic opening in lens that increases or decreases in size to control amount of light that passes through. They are measured in fStops: f2.8, f4, f5.6, f8, f11, f16, f22.
Shutter: Curtain that opens for a specified amount of time, or “shutter speed” to control the amount of light that passes through. These are measured in fractions of seconds.
Exposure: A combination of an aperture and a shutter speed that results in a specific amount of light entering the camera.
Overposure: Too much light entering the camera.
Underexposure: Too little light entering the camera.
Equivalent Exposure: Two combinations of aperture and shutter speed that allow an equal amount of light into the camera. For instance, f8@1/30 equals f5.6@1/60...different numbers, same amount of light.
Depth of Field: The distance between the nearest and farthest objects in a scene that appear sharp.