Many of the controls listed above vary in placement and emplimentation, especially on digital cameras. Digital cameras don't use film, so they don't have any of the film-related parts. Many of the controls for setting F-Stop and Shutter Speed, among others, have been modified on digital cameras to allow easy adjustments with a single control wheel.
Glossary of SLR camera parts and concepts:
Aperature: This is a variable diameter hole in a lens that controls the amount of light passing through at a given moment. It is controlled by the F-Stop setting which is expressed as the ratio of the aperature diameter to the focal length of the lens. For example, f/8 F-Stop indicates that the aperature diameter is 1/8th the focal length distance. A greater F-Stop setting number means a smaller aperature diameter, a greater the depth of field, and a darker image.
ASA: See ASA and ISO.
ASA and ISO: ASA (American Standards Association) and ISO (International Organization for Standardization) are standards for rating the sensitivity of film or CCD arrays. In general, a lower number means less sensativity. Higher ISO/ASA ratings mean greater sensitivity, but an increase in the grainy appearance of the resulting images.
Film advance: You use this lever on film cameras to advance the film during film loading and before each shot to position the next exposure frame behind the lens and shutter. The frame counter is usually displayed here. Digital cameras don't have film advance, and the frame counter is displayed elsewhere electronically.
Film Rewind: When your roll of film is all exposed, you use this to rewind it back into the light-proof container so it can be removed from the camera for processing. Not on digital cameras.
Flash Shoe: If you have one, this is where you can attach an external flash unit.
Focal Length: This is usually expressed in millimeters (mm) and indicates the the distance from the front of a lens to the focal plane of the image. For example, a 50 mm lens, it is approximately 50 millimeters from the front of the lens to the film or CCD. Note: Telephoto lenses are shorter than their focal length designation due to special optics.
Focus Ring: In manual focus mode, you turn this ring to change the distance at which objects will appear focused. Objects further or nearer than the focal distance will appear blurry, varying with F-Stop setting.
F-Stop: See Aperature.
F-Stop Ring: This turn this ring to set the F-Stop setting for the lens. Many modern lenses are electronically controlled and don't have this any more.
ISO: See ASA and ISO.
Motion Blur: When a subject is moving relative to the picture plane, the resulting image will be partially exposed at each position over the period of exposure, and a blurred image will result. The extend of the blur depends on the speed of the subject and the length of the exposure. See Stop Action.
Normal Lens: Lens that provides a normal viewing angle through the lens (focal length is 50 mm for 35 mm camera). These lenses aproximate what you would if you were not looking through the lens. See Telephoto Lens and Wide-angle Lens.
Reciprocity: With film, there is a non-linear curve associated with the exposure rates over time for each of the emulsion grain types (colors) Within their collective "range" these curves are fairly linear, but after very long exposure times, the curves become non-linear, and at different rates. This results in reciprocity faliure, and color shifts will result as one grain type (red for example) will keep reacting to the prolonged exposure while the other two (blue and green) have stopped reacting to the light. Reciprocity is not an issue with digital camera sensors.
Shutter: The shutter opens to allow light to enter the camera body and expose the film or CCD. See Shutter Speed.
Shutter Release: You press this to expose the image by opening the shutter, and stopping down the aperature. Most newer camera shutter releases are pressed half-way before each shot, to activate the light metering, auto focus, and power up the view finder display so other settings can be monitored while composing the shot. Older cameras allow a shutter release cable to be fastened to the shutter release to allow shutter control without having to touch and consequently shake the camera body during exposures. Newer cameras have an equivelent electronic control which plugs into the body via a chord, or communicates wirelessly with the camera.
Shutter Speed: This determines the amount of time that the shutter will be opened, allowing light to pass through the lans and expose the film or CCD matrix. There is usually a "bulb" setting that allows you to hold the shutter open for as long as you press the shutter release. Slower shutter speeds decrease the grainy appearence in images. Higher shutter speeds decrease motion blur in images.
Stop Action: Even when a subject is moving relative to the picture plane, a very high shutter speed can be used to "stop" the action and eliminate motion blur. This requires faster lenses and bright lighting conditions. See Motion Blur.
Telephoto Lens: Lens that provides a narrower than normal viewing angle through the lens (focal length greater than 50 mm for 35 mm camera). These lenses magnify the image and allow you to zoom in on far-away subjects. See Wide-angle Lens and Normal Lens. Note: Technically, a telephoto lens has special telephoto optics which allow the physical length of the lens to be much shorter than the focal length, though the term is widely used for lenses of higher focal lengths (above 50 mm for 35 mm cameras) regardless of their physical length.
Tripod: A stable device with 3 variable length legs and a head to which a camera is attached to provide shake-free exposures, when compared to hand-held exposures. The head should have three degrees of movement (up-down, side-to-side, and tilt), as opposed to most video tripods, which only have two (up-down and side-to-side). This allows you to set the camera even with the horizon and/or rotate the camera 90 degrees for vertical shots.
Tripod Mount: For slower shutter speeds (depending on how steady handed you are, your type of lens, and whether you have image stabalization technology) it is often desirable to mount your camera to a stable tripod, or other stablization device. The threaded hole in the bottom of your camera is for this. If you have a large telephoto lens, you would mount the lens rather than the camera body to the tripod.
View Finder: You look through this to preview and compose your pictures. The aperature is usually wide open so you can see the image clearly while you compose your shot. Most SLR cameras have a button that will let you see the image with the aperature closed down to the diameter it will be when the picture is taken, so you can access the depth of field. You may also see other settings displayed within the view finder such as exposure (light meter), F-Stop , Shutter Speed, and ISO setting.
Wide-angle Lens: Lens that provides a wider than normal viewing angle through the lens (focal length less than 50 mm for 35 mm camera). Some extreme wide-angle lenses are called fish-eye lenses and can provide a view angle of 180 degrees or more. See Telephoto Lens and Normal Lens.
Zoom Lens: This type of lens allows you to change the focal length by turning a zoom ring on the lens. One might think that moving closer to a subject would have the same effect as "zooming in" from a greater distance to get the same viewing angle, but this is not the case. The geometry of an image changes as you get closer to a subject so that relative sizes are exaggerated with their relative distance from the lens. For example, when you get "close" to someone's face, their nose looks bigger than usual, because it is closer to the camera.
Zoom Ring: On lenses with zoom capability, you turn this ring to zoom in and out on the subject. While this feature gives you greatly increased composition control, it requires added optics and mechanics in the lens assembly, and can result in slightly less over-all image sharpness.