Are you new to photography? Baffled by terms some manufacturers use when describing their products? Below are some of the most common terms and their meanings used in photography today.
|
Compact digital camera
|
A digital camera that does not take interchangeable lenses (though some take converter lenses). Compact digital cameras range from simple point-and-shoot to ones with advanced settings and manual and semi-automatic control. |
| DSLR | Standing for single-lens reflex, these are higher-end digital cameras revered by serious photographers. The digital versions of SLRs work in this manner: the shutter retracts so an image can be recorded. One of the prime benefits of using a digital SLR camera is that lenses are interchangeable. |
| Pixel | (PICture ELement) The smallest element of a digitised image. One small dot of light among the many dots that make up an image on a computer screen. |
| Megapixel | A unit equal to one million pixels. The higher the resolution, the more pixels in an image and therefore the greater the image quality. An image file that is 1 megapixel (MP) can make a photo realistic print of 5 x 7 inches; a 2 MP file can make an 8 x 10-inch print; a 3 MP file can make an 11 x 14-inch print. |
| Resolution | The number of pixels in an image. A higher number correlates to a higher quality image. |
| DPI | Dots Per Inch. Number of dots a printer or device (like a monitor) can display per linear inch. For example, most laser printers have a resolution of 300 dpi, most monitors 72 dpi, most PostScript image setters 1200 to 2450 dpi. Photo quality inkjet printers now range from 1200 to 2400 dpi. |
| Megabyte | An amount of computer memory consisting of about one million bytes. The actual value is 1,048,576 bytes. |
| JPEG | A standardized format used by many digital cameras for storing images. This format is also commonly used for images on the web and images attached to e-mail messages. JPEG, which stands for Joint Photographic Experts Group, the group that established this file standard, is one of the most widely used formats today. JPEG is a standardized image compression mechanism designed for compressing full-colour or grey scale images of natural, real-world scenes. JPEG uses lossy compression, which can damage image quality. |
| LCD | Liquid Crystal Display. A full-colour display screen on cameras used to preview and review pictures and view information, such as menu options and camera settings. |
| Memory card | A storage device used to store data, such as picture and movie files. Available in a range of sizes, such as 8 MB, 32 MB, and 256 MB. |
| Aperture | A small, circular opening inside the lens that can change in diameter to control the amount of light reaching the camera's sensor as a picture is taken. The aperture diameter is expressed in f-stops; the lower the number, the larger the aperture. For instance, the aperture opening when set to f/2.8 is larger than at f/8. The aperture and shutter speed together control the total amount of light reaching the sensor. A larger aperture passes more light through to the sensor. Many cameras have an aperture priority mode that allows you to adjust the aperture to your own liking. |
| Shutter speed | The camera's shutter speed is a measurement of how long its shutter remains open as the picture is taken. The slower the shutter speed, the longer the exposure time. When the shutter speed is set to 1/125 or simply 125, this means that the shutter will be open for exactly 1/125th of one second. The shutter speed and aperture together control the total amount of light reaching the sensor. Some digital cameras have a shutter priority mode that allows you to set the shutter speed to your liking. |
| Depth-of-field (DOF) | Refers to how much of a photo is in focus when the camera is focused on the main subject. Depth-of-field is controlled by a camera's aperture, in conjunction with the focal length of the lens. Deep (more) depth-of-field means that all or most of the picture is in focus from front to back. Shallow (less) depth-of-field means that a subject is in focus but objects in front and behind it appear out of focus. |
| CD-R | CD-Recordable: a compact disc that holds either 650 or 700 MB of digital information, including digital photos. Creating one is commonly referred to as burning a CD. A CD-R disc can only be written to once, and is an ideal storage medium for original digital photos. |
| CD-RW | CD-Rewritable: similar in virtually all respects to a CD-R, except that a CD-RW disc can be written and erased many times. This makes them best suited to many backup tasks, but not for long term storage of original digital photos. |
| Red-eye | The red glow from a subject's eyes caused by light from a flash reflecting off the blood vessels behind the retina in the eye. The effect is most common when light levels are low, outdoor at night, or indoor in a dimly-lit room. |
| RGB | Red, Green, and Blue: the three colours to which the human visual system, digital cameras and many other devices are sensitive. |
| Saturation | How rich the colours are in a photo. |
| RAW | The RAW image format is the data as it comes directly off the CCD, with no in-camera processing is performed. |
| USB | Universal Serial Bus: a protocol for transferring data to and from digital devices. Many digital cameras and memory card readers connect to the USB port on a computer. USB card readers are typically faster than cameras or readers that connect to the serial port, but slower than those that connect via FireWire. |
| White balance | A function on the camera to compensate for different colours of light being emitted by different light sources. |
| ISO speed | A rating of a film's sensitivity to light. Though digital cameras don't use film, they have adopted the same rating system for describing the sensitivity of the camera's imaging sensor. Digital cameras often include a control for adjusting the ISO speed; some will adjust it automatically depending on the lighting conditions, adjusting it upwards as the available light dims. Generally, as ISO speed climbs, image quality drops. |
| Underexposure | Improper exposure causing an image to look too dark. There is a loss of detail in dark areas. |
| Overexposure | Improper exposure causing an image to look too light. There is a loss of detail in bright areas. |
| Shutter lag | The delay that takes place between pressing the shutter-release button and the time a photo is actually taken. Shutter lag times vary from digital camera to digital camera. |
| Noise | Randomly-spaced speckles (pixels) that can appear in digital images shot at high ISO numbers. Noise results in a reduction of photo detail and clarity, though it can be reduced with special noise reduction software. Noise is most visible when photos are shot at ISO 200 and above with a consumer digital camera. Some digital cameras have a Super CCD where photos taken at higher ISO numbers (eg. ISO 1600) have little, if any, visible noise . |
