The camera is such a common object in modern life that it's easy to take it for granted. Especially in the digital age, you might forget about all the moving and non-moving parts that make a camera function. Whether you're still shooting film or thoroughly enjoying your new DSLR, it's important to understand how this machine works.
From the moment you look through the viewfinder and your finger presses the shutter button, you're engaging a camera's operation. It's all designed to capture a photograph using light. Once you understand how each part of a camera body works, you can have a better understanding of how to take great photographs.
The viewfinder is the hole in the back of the camera that a photographer looks through to aim the camera. Some viewfinders use a mirror inside the camera to look "through the lens" (TTL). Other viewfinders are simply holes through the body of the camera.
TTL viewfinders allow the photographer better accuracy when composing their images. This is because what you're seeing is exactly what the lens is seeing. In a digital single lens reflex (DSLR) camera, it is an optical TTL viewfinder. Other cameras may have an electronic TTL viewfinder.
Rangefinders, on the other hand, are slightly off. The hole you look through in the viewfinder is parallel to but not lined up completely with what the film plane sees. Photographers need to compensate for the deviation when composing the photo.
Additionally, on many digital cameras, you do not have to look through the viewfinder. You have the option of composing the image on an LCD screen on the back of the camera.
The shutter release is a button that raises a shutter inside the camera for a specified amount of time to allow light to expose the film. Essentially, it's the trigger and how you physically tell the camera to take a picture.
Depending on the type of camera, the shutter button has a number of other functions as well:
- In some single lens reflex (SLR) cameras, this button also raises a mirror that allows the photographer to use the viewfinder to look through the lens itself.
- For autofocus cameras, including DSLRs, point and shoots, and some 35mm film SLRs, pressing the shutter button halfway focuses the lens.
- In automatic film cameras, the shutter release also causes the film to advance to the next exposure. In manual film cameras, there is a "film advance lever" that must be turned in order to advance the film and the exposure counter.
Many SLR cameras also allow you to remotely engage the shutter via a cable release or wireless remote.
The shutter is an opaque piece of metal or plastic inside your camera that prevents light from reaching the film or digital sensor. The shutter is opened, or released, by the shutter release button. The amount of time the shutter stays open is controlled by the shutter speed setting.
In digital cameras, you will not be able to see the actual shutter. However, if you open up the back of a film camera, the shutter—typically a curtain or blades—is visible.
Shutter Speed Control
The shutter speed control is the place on the camera where you set the amount of time the shutter will remain open. The shutter speed is measured in fractions of a second but is generally shown as the denominator only. For example, 1/60 of a second is shown as 60.
- On automatic cameras, the shutter speed control is generally accessed through a menu. This exposure information is displayed on the camera's screens (on the top of the camera body, inside the viewfinder, and on the LCD screen).
- In manual cameras, the shutter speed is generally controlled and displayed on a knob on the top of the camera.
The f-stop control is where you will select the appropriate aperture (the size of the shutter's opening). It, along with the shutter speed, are the two main factors used to control the exposure of a photograph.
- On automatic cameras, the f-stop control is on the camera and uses the wheel or dial that doesn't control the shutter speed. The f-stop reading is next to the shutter speed on the camera's screens and is generally just a number (e.g., 3.5, 5.6, 8,11, etc.).
- For older manual cameras, the f-stop is controlled on the lens via a ring that is separate from the focusing ring.
Film Speed or ISO Control
The film speed control allows you to calibrate your camera's meter to the film speed so that you will get an accurate exposure reading. The film speed may be set electronically through a menu on automatic camera or via a knob on manual cameras.
- On manual cameras, the control is often integrated with a film speed indicator on the top of the camera.
- On automatic cameras, the control and film speed indicator are generally separate with the film speed being indicated on the electronic menu display on the camera's menu.
In digital photography, film speed is referred to as ISO (a term carried over from film meaning "International Organization for Standardization"). This can be changed based on lighting conditions using the camera's menus. Though it is convenient to use a higher ISO when shooting in low-light situations, keep in mind that the image will also be more pixelated.
In film cameras, there is a compartment in the back of the camera to hold the film. This compartment has a space for the film canister, sprockets to guide the film across the exposure area, a pressure plate to tighten the film, and a take-up reel to wind the film.
When the roll of film has been completely exposed, automatic cameras use a small motor to rewind the film. Manual cameras require the photographer to turn a small "rewind knob" to manually rewind the film into the canister. If the film is not rewound before the back compartment is opened, the film will be exposed to enough light to ruin the images.
In digital cameras, the film compartment is replaced with an array of electronics that makes the camera function but stays hidden to the photographer. Among these internal parts is a digital sensor, which is a solid-state device that captures the light much as a piece of film does. The information is then transferred through the camera to form the digital image that appears on the LCD screen and is stored on the digital media card.
Sensors are a technology that is constantly changing as improvements are made. It is, however, the heart of a digital camera and will affect the quality of every image that particular camera takes. Unlike film, you cannot change a sensor if it doesn't meet your expectations.
Most cameras now include a built-in flash. Some are simple light bulbs built into the front of the camera. On SLR cameras, most built-in flashes pop-up out of a protective storage area on the top of the camera.
External flashes can often be attached via the "hot shoe mount." On older manual cameras, there is a small connector port on the front of the camera that accepts a cable attached to a distant flash.
Hot Shoe Mount
The hot shoe mount is a point on the top of most SLR and DSLR cameras where an external flash can be connected. It is called a "hot shoe" because it has electrical contact points and guide rails that fit over the bottom of the flash like a shoe.
Typically, the hot shoe mount is just above the viewfinder. On some older cameras, it may be off to one side.
Lens Ring Mount
On cameras that allow for interchangeable lenses, there is a metal ring on the front of the camera where the lens will attach. This ring contains electrical contact points to connect the lens controls to the camera body. There is a small button or lever to the side of this mount called the "lens release button" that releases the lens from the body.