High Speed Photography

it's important to first go over the basics of photography and what makes a camera work. More specifically, it helps to understand how manual cameras work rather than newer automatic and digital cameras. Although it's possible to take photographs of high-speed objects with automatic and digital cameras, when it comes to high-speed photography, the more manual a camera is, the more successful the photos will be. We'll therefore focus on manual single-lens-reflex (SLR) cameras and the basic principles of photography.

One of the most important parts of a camera is, of course, the lens. A lens is a simple, curved piece of glass that bends and redirects incoming light to form a real image, or an exact reproduction of the scene in front of the camera. Light bent through the lens is essentially "painted" onto the film inside the camera; in fact, it's no surprise that the root of the word "photography" is Greek, meaning "drawing with light." The first factor, the amount of light coming onto the film, is controlled by the camera's aperture, which is a circular opening that can expand or shrink in size. The aperture works just like the iris of your eye -- when you need to let in more light, the circle becomes bigger; when you need to block out some light, the circle becomes smaller. A set of numbers on the aperture control of a camera called f-stops describe the size of the circle. The f-stop is inversely related to the size of the aperture: The higher the f-stop number, the smaller the opening. The device that works with the aperture and determines the second factor, how long the film is exposed to light, is called the shutter. The shutter is basically a curtain that opens and closes to expose the film to light. More specifically, it's the shutter speed -- the rate at which the shutter opens and closes -- that really affects the film's exposure.