Sony Digital Camera
Digital Camera: Buyers Guide
|The aperture in a camera determines how much light strikes the CCD, a small f number on the camera indicates a larger aperture, and a large f number indicates a smaller aperture. Many cameras allow you to change the f number, which corresponds to the aperture size. The f number corresponds to how big the aperture is in relation to the lens. A f/4 aperture setting means that the aperture is one quarter the size of the lens. A f/10 setting means that the aperture is one tenth the size of the lens.
|Some lenses will create what is known as “barrel distortion” around the edges of a picture. Any straight lines will appear slightly curved, due to the spherical shape of the lens.
|The buffer is the internal memory in the digital camera, it stores the pictures after the information comes off of the CCD. The internal memory also helps in burst shooting, as it will hold a number of pictures as the camera takes pictures.
|Camera lag can come in different forms, before the picture is taken there can be some lag as the camera prepares to take the picture. After the picture there is lag as the camera processes the image and stores it to memory.
|CCD stands for Charged-Couple Device. The CCD is the part of the digital camera that converts light to an electric signal useable by the digital camera’s electronics. The CCD is made up of (usually) millions of tiny sensors that record the amount of light that hits them, each sensor contains the information for one pixel. The sensors only record the amount of light that hits them, not the color of the light. For the digital camera to detect what color is in each pixel, a special method is used. To capture color, the digital camera applies a color filter over the individual sensors, the filter is usually applied directly to the CCD using dye.
|The “purple fringing” effect. Is visible in some cameras around the corners of high contrast objects in a photograph.
|The storage of data in the form of binary numbers, 0 and 1. Digital information can be copied and stored with no loss of information.
|A digital zoom is not a true zoom, to zoom the camera will take the center of the image and interpolate it to the original size. An optical zoom is preferred over a digital one.
|Stands for Digital Print Order Format. When using DPOF, it creates a file on your memory card that can be used to tell printing services and applications what images it wants printed, how many copies of each images are to be printed, and other picture information.
|Many cameras are sold with the total number of pixels on the CCD being advertised, not the number of pixels the image is captured at. For example the Olympus C-3030Z is sold with a 3.34 megapixel CCD, it captures pictures at 2048*1536, multiplying this out we get 3,145,728 effective pixels, or 3.14 megapixels.
|Stands for Exposure Value, basically means the ability to lighten or darken an image.
|The focal length on a digital camera is usually related to the 35mm equivalent, due to the fact that the CCD’s on digital cameras are much smaller than the areas exposed on a 35mm camera. So a camera that states that it has a 38mm lens is really reffering to the 35mm equivalent, even though the actual lens may only be around a 6mm lens.
|Some cameras will expand the photo into a larger image. This is called interpolation. Interpolation mathematically makes up the extra pixels in the image, and although interpolation works well it is still artificially increasing the size of the image.
|ISO settings on you 35mm camera refer to the efficiency of the film and how it responds to light. (e.g. ISO 100, ISO 200, etc.) With a digital camera it is essentially the same in the fact of how the light is interpreted by the camera. The lower the ISO setting, is essentially the slower the processing of the light, so lower ISO settings are more suited to brighter light.
|JPEG is named after the committee that designed it, the Joint Photographic Experts Group. The JPEG method is based on the fact that humans are much more aware of small changes in brightness (luminance) than small changes in color or large changes in color or brightness. The JPEG compression algorithm works well and can easily achieve a 10:1 or 20:1 (or more) compression ration, depending on the compression settings, with minimal visible image quality loss.
|Stands for Liquid Crystal Display. This is usually the small screen on the back of the digital camera, though not all cameras have them. Used to display camera information, menu systems, and can be used as a viewfinder. Most LCD’s are difficult to see in bright sunlight, due to the fact that the sun’s rays overpower the light being emitted by the screen.
|A megapixel is 1 million pixels. The number of pixels is determined by multiplying the number of pixels on the horizontal by the number of pixels on the vertical. For example a digital camera with a 1280*1024 pixel resolution will have 1,310,720 pixels total. This means that a camera with that resolution will be approximately labeled as a 1.3 megapixel camera. Some manufacturers will state that their camera has a certain number of megapixels when in fact the camera only uses a percentage of these pixels, this is called the effective number of pixels.
|An optical zoom physically changes the length of the lens to increase the zoom on the camera. This type of zoom is the best because it does not need to interpolate the results.
|A pixel is one dot that carries the information from the optical sensor on the CCD to the image itself. Each pixel displays one color and all of the pixels together produce the image.
|The shutter is a device which limits how long light strikes the CCD, the amount of light is determined by the shutter speed and the aperture setting. The shutter differs between digital cameras, some will use a physical shutter, and some use an electronic shutter. The physical shutters will allow light to strike the CCD by letting light past some kind of physical barrier. The electronic shutters will turn the CCD on for the time allotted by the shutter speed.
|Shutter Release Button
|This is the button that you use to take your picture, this button is sometimes used to prepare the camera for picture taking. Pressing the shutter release button halfway may (depending on your camera, and its settings), focus the autofocus, prepare the flash, adjust the whitebalance, exposure time, and shutter speed. Pressing the shutter release button all the way down will open the shutter and the picture will be taken.
|The shutter speed is the length of time that the CCD is exposed to light. Shutter speed times range from very short, up to 1/10000 of a second to infinitely long. Small shutter speeds are better for action shots.
|The white balance relates to what the camera determines as the color white in the image. Different light conditions will result in the color white appearing differently. Some cameras will offer automatic white balance, this will allow the camera to choose the white setting based on what it thinks should be white in the picture. Sometimes this will be a problem is there is a dominant color in the picture that is not white. Other cameras have a number of white balance presets, including fluorescent, sunlight, cloudy, and others.