I thought it might be helpful to start a running 'dictionary' of photography terms, for us novices who don't know much beyond "point" and "click". With the help of our resident experts, maybe we can all learn some of the lingo! If someone would please help define these, we can keep adding to the list as we go. SLR Aperture Focal Length
Re: Dictionary of Photography Terms for Novices Aperture = Lens opening. The opening in a camera lens through which light passes to expose the image. The size of aperture is either fixed or adjustable. Aperture size is usually calibrated in f-numbers-the larger the number, the smaller the lens opening. f2.8 is a larger apeture than f8 and as such lets more light into the camera during the same exposure length (f2.8 at 1 second is 3x more light than f8 at one second). Changing aperture affects 1. more/less light at the same exposure length and 2. more/less depth of field (how much of the photo is in focus vs. how much is blurry). Generally lenses tend to be sharpest from f/8 to f/11, aka sweet spot. The aperture scale is a sequence of numbers based on 1.0 and 1.4 and is expressed on a scale as follows: f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/45, f/64, f/90, f/128. each step along the way can be referred to as a "stop" and represents either a doubling or halving of the light passed through depending on which way you go. as you go from left to right (numbers getting bigger) you are halving the light and vice versa. There are also intermediate numbers along the sequence such as f/6.3 and f/7.1 etc. but that only complicates this definition. for a complete discussion on aperture, go to http://en.wikipedia.org/wiki/F-number#S ... d_exposure Focal Length = The distance between the film and the optical center of the lens when the lens is focused on infinity. The focal length of the lens on most adjustable cameras is marked in millimeters on the lens mount. The rule here is 'the larger the number in mm, the more "zoomed in" you are'. Lens Element = each individual piece of glass in the lens Lens Group = Several elements optically cemented together to act as a single element. SLR = Single Lens Reflex. A camera in which you view the scene through the same lens that takes the picture. An SLR camera "views" the scene through the main lens and uses a mirror and a prism to put the scene into the viewfinder. Camera with interchangeable lenses and no built in lenses are known as SLR cameras.
EXPOSURE = ISO + SHUTTER + APERTURE how much light is captured is controlled by the shutter, aperture, and ISO (film speed) to produce an EXPOSURE. The shutter is akin to the shutters on your house. When the shutter is closed, no light enters the camera even though the light is entering the lens. When the shutter is open, light enters the camera through lens and strikes the previously mentioned medium, causing an image to be recorded. The shutter is expressed in the time in which it is open, and is expressed in terms of time, such as 1/60 second, 1/125 second, etc. It is usually shown on the camera as a whole number, such as 60. In the event of shutter speeds of greater than one second, the camera usually shows the number with a quotation mark, such as 3â€
