| Aberration- is the failure of a lens to focus all colors to the same point. It occurs because lenses have a different refractive index for different wavelengths of light (the dispersion of the lens). The refractive index decreases with increasing wavelength. |
| Accessories- add-on pieces of equipment for a digital camera that usually must be purchased separately from the camera itself. |
| Aperture- the size of the adjustable opening inside the lens, which determines how much light passes through the lens to strike the image sensor. A digital camera's aperture is measured in f-stops, and higher f-stops signify a smaller amount of light. The aperture changes, depending on the camera's settings for a particular shot. |
Auto Exposure- an automated digital camera system that sets the aperture and/or shutter speed, based on the external lighting conditions for the photo. With beginner-level digital cameras, photographers usually can select one of three different AE modes. |
| Auto Focus- a capability of a digital camera to automatically bring the subject of a photograph into sharp focus before capturing the digital image. Most beginner-level digital cameras only allow auto focus. Manual focus usually is limited to advanced digital cameras. |
| B |
| Battery- the portable electric power source used to operate a digital camera. |
| Bias- |
| Body- the primary portion of the digital camera, which contains the controls, the LCD, the internal image processor, and the associated circuitry. |
| Burst Mode- a digital camera feature where the unit captures a set number of photos in a short amount of time. For example, in one type of burst mode, a digital camera might capture 10 photos in three seconds. |
| C |
| CCD (Charged Coupled Device)- the silicon chip inside the digital camera that records the image. |
| Compact Flash- a type of flash memory card used in digital cameras to store data about images. CF cards are available in two configurations: Type I and Type II. Type I cards are slightly thinner than Type II cards. If a digital camera has a CF Type I slot, it cannot use Type II memory cards. However, digital cameras with CF Type II slots can read both types of CF cards. |
| Continuous Shot Mode- also known as burst mode, is a digital camera feature where the unit captures a set number of photos in a short amount of time. For example, in one type of burst mode, a digital camera might capture 10 photos in three seconds. |
| Conversion Lenses- small pieces of lens hardware that fit over lenses on a limited number of digital cameras, providing slightly increased zoom or wide angle capabilities. Three types of conversion lenses exist: -- Telephoto, or zoom, conversion lenses provide additional magnification capabilities. -- Wide angle conversion lenses increase the scope of the lens to place more detail in the shot. -- Macro conversion lenses improve the capability of the lens to choose extreme close-up photos. |
| D |
| Depth of Field- the section of the digital photograph in front of and behind the subject that will be in focus, too. Any objects outside of the scene's depth of field (DOF) will appear out of focus, or fuzzy. The distance to the subject, the aperture, and the focal length all affect depth of field in a photograph. With a shallow, or narrow, depth of field, the subject will be in focus, along with anything a few feet in front of and behind the subject. With a great, or wide, depth of field, the subject will be in focus, along with anything several to dozens of feet in front of and behind the subject. |
| Digital Zoom- the magnification of a digital image using software inside the digital camera, rather than changing the focal length of the zoom lens to magnify the image. Digital zoom simply increases the size of the pixels that make up the digital image, which can harm photo sharpness. Digital photographers prefer optical zoom. |
| DSLR- or single-lens reflex, digital camera is a high-end model aimed at intermediate and experienced photographers. A digital SLR camera often is called a DSLR. DSLR cameras are professional-style cameras. DSLR models typically offer interchangeable lenses, full manual controls, external flash units, and through-the-lens (TTL) viewfinders. They're large models and they closely resemble the 35mm film cameras that were popular several years ago, with handgrips and large lens housings. |
| E |
| Effective Resolution- the measurement of the total number of pixels that a digital camera's image sensor uses to actually collect data about a photograph. Contrast effective resolution with overall resolution, which is the measurement of the number of pixels the image sensor contains. However, not every pixel on an image sensor is used to collect data about a photograph. Digital camera resolution is expressed in megapixels, which are millions of pixels. In a listing of digital camera specifications, you'll probably see both overall and effective resolution measurements. Effective pixels, or effective resolution, is the more useful number. |
| Exposure Metering- the digital camera's built-in system that measures the amount of external lighting in a scene and then determines the best automatic settings for the photograph. Three modes of exposure metering are common: --Center weighted metering is a mode where the digital camera measures the external light in an area around the center of the frame. It works best for portrait photos. --Matrix metering is a mode where the digital camera divides the scene into segments, measures the lighting level in each segment, and then determines the automatic settings based on which settings would be correct for the largest number of segments. This mode, sometimes called multi-segment metering or multi-pattern metering usually has the best exposure results. --Spot metering is a mode where the digital camera only measures the lighting in a tiny spot in the center of the frame. |
| External Flash- a piece of add-on equipment that creates an artificial source of intense light that can be added to photos shot with a digital camera. The external flash unit is not permanently attached to the camera. |
| F |
| F-Stop- short for focal-stop, is the numerical measurement of the aperture settings in a digital camera lens. A higher f-stop setting means more light is allowed through the adjustable opening inside the lens to strike the image sensor. |
| File Formats- a digital camera are the types of formatting used to store digital image files. Each of the three primary types of formatting offers a few different benefits and drawbacks. --JPEG, short for Joint Photographic Expert Group, is the most commonly used format for digital images, especially for beginner photographers. JPEG, pronounced jay-peg, is a form of compression that reduces the file size significantly, allowing you to fit more photos on a memory card. --TIFF, short for Tagged Image File Format, uses a slight compression to reduce the file size. --RAW is the file format that's closest to film-quality, requiring a lot of storage space. The digital camera does not compress or process a RAW file. |
| Firewire- is the brand name for a serial bus standard that allows high-speed data transfers. The official name of the standard is IEEE 1394. |
| Film Plane- the precise location where the focused image from the lens meets the film or digital sensor inside a camera body. |
| Fixed Lens Camera- an advanced digital camera that looks like a digital single lens reflex (DSLR), but that cannot use interchangeable lenses. Fixed lens cameras typically offer very large zoom lenses, and they usually cost more than point and shoot, beginner models. Some fixed lens cameras can slightly add to their zoom and wide angle capabilities through the use of conversion lenses. |
| Flash- an artificial source of extremely intense light that can be added to photos shot with a digital camera. The flash fires just before the photo is snapped, giving the lens and image sensor plenty of light with which to record the digital image. Flash can refer both to the flash of light that occurs when the flash fires, as well as the actual flash unit that creates the light. |
| Flash Memory- is the storage medium used with digital cameras. The flash memory card can retain the stored data without the need for continual power. Several different brands of flash memory cards, also called memory cards, exist, and digital cameras can only use specific brands. Each brand is a different size, and memory cards are not interchangeable. |
| Focal Length- is the distance from the center of the lens in the digital camera to the focal point. Focal length is measured in millimeters, and it's usually expressed as a 35mm film equivalent. |
| Focus Lock- the feature in the auto focus system of a digital camera that allows the camera to pre-focus on a subject, eliminating most shutter lag and allowing for sharp photos, even when the subject moves out of the center of the frame. Shutter lag is any delay between the time the shutter button is fully depressed and the time the image sensor actually records the image. |
| G |
| Glossy Photo- the media finish used for printing digital photographs. |
| H |
| HD (High Definition)- usually shortened to HD video, is a type of video clip that has a high resolution, usually at least 1024x768 pixels. Although nearly all new still digital cameras can shoot video clips, not all of them can shoot HD video. Some digital cameras can shoot HD video, but only at certain lower-speed frame rates. |
| Hot Shoe- a connector on a digital camera where the photographer can connect a variety of devices, such as an external flash unit or a geotagger/GPS receiver unit. Most beginner-level digital cameras do not have hot shoe units, which usually are only available on digital SLR models. The hot shoe connector usually is in the middle of the top panel of the digital camera. |
| I |
| Image- the optical counterpart of an object produced by an optical device (as a lens or mirror) or an electronic device; a visual representation of something such as the likeness of an object produced on a photographic material; a picture produced on an electronic display (as a television or computer screen) |
| Image Sensor- a chip inside a digital camera that records a photo or an image. As light enters the digital camera lens, it strikes the image sensor. The image sensor then converts the light to electrical charges, which eventually become the pixels that make up the photo. CCD and CMOS are the two types of image sensor technologies found in a digital camera. CMOS is becoming the more popular type of technology because of its low power consumption and speed. The number of pixels an image sensor contains determines the resolution of the digital camera. By multiplying the number of pixels the image sensor contains horizontally and vertically, you can determine the maximum resolution of the image sensor, listed in megapixels (MP). |
| Image Stabilization- is a digital camera technology that works to reduce blurry photos caused by camera shake. Image stabilization is available in one of three configurations. |
| Interchangeable Lenses- are pieces of equipment primarily found with high-end digital cameras, also called digital SLR cameras. With multiple interchangeable lenses, the photographer can achieve different photographic images. Some lenses provide strong zoom capabilities, for example, while others provide wide-angle capabilities. |
| ISO- is a number used to express the light sensitivity of the digital camera. ISO has its origins in film photography, where the ISO setting measured the sensitivity of a particular roll of film to light. With a digital camera, you usually can shoot at a variety of ISO settings. Higher ISO settings allow you to shoot digital photos in low-light conditions, but such photos are more susceptible to noise and grainy images than photos shot at low ISO settings. |
| J |
| JPG or JPEG- short for Joint Photographic Expert Group, is the most commonly used type of formatting for image files created with a digital camera. JPEG, pronounced jay-peg, is a form of compression that reduces the file size significantly, allowing you to fit more photos on a memory card. JPEG is especially useful for beginner photographers. |
| L |
| Landscape Mode- the technique of shooting a photo that has a horizontal orientation. Landscape photos have greater width than height. |
| LCD (Liquid Crystal Display)- is the display technology used to create the screens embedded in the back of nearly all digital cameras. In a digital camera, the LCD works for reviewing photos, displaying menu options, and serving as a live viewfinder. |
| M |
| Manual Mode- the settings on a digital camera that the photographer controls manually. For example, a photographer may want to set the shutter speed and aperture manually to create a particular look in a photograph. The ability to manually control certain settings on the digital camera usually is limited to advanced models. |
| Matte Photo- a non-reflective print paper surface for digital imaging. |
| Megapixel- is equal to 1 million pixels. A pixel is an individual element of a digital image. The number of megapixels determines the resolution of an image, and a digital image with more megapixels has more resolution. |
| Memory Stick or Card- is a small, flat, electronic device that fits inside a digital camera and is used to store data about digital images. Several different brands of memory cards exist, and digital cameras can only use a specific brand or brands. Each brand is a different size, and most memory cards are not interchangeable. |
| Movie Mode- is the capability of a still digital camera to shoot video clips. Nearly all new still digital cameras include at least basic movie modes. Improvements in video capabilities for digital still cameras continue at a rapid rate. Some digital still cameras can even shoot HD video. |
| N |
| Noise- is any of a series of unwanted variations that appear in a digital camera photo. Noise appears as strangely colored or grainy pixels in a photo, especially as purple edges to objects, called purple fringing. Noise in a digital image is especially common in photos shot in low light. Noise occurs because of electrical variations and interference in the image sensor. High ISO settings can create noise. |
| O |
| Optical Viewfinder- a small window at the top and back of the digital camera that you use to frame your photograph and that attempts to match the path of the main lens. Some high-end digital cameras link the optical viewfinder to the lens, meaning the viewfinder looks through the lens, using a series of mirrors and prisms. |
| Optical Zoom- the magnification of a digital image using physical changes in the focal length of the zoom lens to magnify the image. Optical zoom is the preferred method of magnifying an image for digital photographers because it doesn't negatively affect image quality, as does digital zoom. |
| P |
| Panorama Mode- a digital imaging feature by which a photographer can stitch together, or combine, a set of photographs to create a single, panoramic image. Panorama mode can be achieved by software inside the camera, post-processing computer software, or a special panoramic machine. A panoramic image provides a wide-angle shot, usually covering 180 degrees or more. |
| Pixel- short for picture element, is the smallest piece of information that makes up a digital image. |
| Point and Shoot- a beginner-level model that often automatically controls all settings for shooting the photograph, such as deciding whether to fire the flash or increase the shutter speed. Point and shoot models are the most affordable types of digital cameras. |
| Portrait Mode- the technique of shooting a photo that has a vertical orientation. Portrait photos have greater height than width. With beginner-level cameras, you have to turn the camera 90 degrees to shoot a portrait mode photo. |
| Print- The physical representation of the digital image, usually reproduced by inkjet or light sensitive photo paper. |
| Processor- a digital camera is a chip that controls most aspects of image management and creation. A processor can improve image quality, increase the speed of the camera's auto-focus system, improve image compression results, and preserve battery life. The camera's processor also controls the memory card, the LCD, and the analog/digital converter. |
| R |
| RAW- is the file format used with digital photographs that's closest to film-quality, requiring a lot of storage space. The digital camera does not compress or process a RAW file in any way. Some people refer to RAW format as a "digital negative" because it doesn't change anything about the file when storing it. |
| Redeye- is an effect often seen in digital photographs and prints, where the subjects appear to have red-colored pupils in the eyes when a flash is used when shooting the image. Redeye is caused by a reflection from the light from the flash against blood vessels in the retina of the eye. Beginner-level and low-priced digital cameras are more susceptible to causing redeye than advanced models, because the lens and flash units usually are close together in a low-priced digital camera. |
| Resolution- is the measurement of the total number of pixels that a digital camera's image sensor can record in one photograph. Digital camera resolution is expressed in megapixels, which are millions of pixels. |
| Response Time- the collection of times, or delays, that occur as a digital camera functions, including startup time, shutter lag, and shot to shot delays. |
| S |
| Scene Modes- are pre-set exposure modes on beginner-level digital cameras that help inexperienced photographers achieve the proper automatic settings for a photo. By using a scene mode, the photographer is telling the digital camera to emphasize a certain aspect of the settings for a particular set of upcoming photos. |
| Secure Digital- a type of flash memory card used in digital cameras to store data about images. SD is probably the most popular type of memory card. SD and MMC flash memory cards are similarly sized and use similar technology as SD's design was based on MMC's design, but not all digital cameras can use the two types of cards interchangeably. Mini SD and Micro SD cards are available, too, but they typically work with cell phones, rather than digital cameras. Adapters are available to make a Mini SD or Micro SD card work in a digital camera that uses SD memory cards. |
| Self Timer- a feature of a digital camera where the camera shoots the photo automatically after a delay. The photographer lines up the photo as desired, sets the self timer for a delay for anywhere from 1 to 15 seconds, and then walks into the frame, becoming a subject in the photo. Once the set time passes, the self timer tells the digital camera to shoot the photo. |
| Shooting Modes- are various automatic modes found with point and shoot cameras that the photographer can set and that help ensure proper lighting and focus. For example, when photographers are going to shoot nature photos, they can set the shooting mode to Landscape Mode, which will greatly increase the chances of a properly exposed photo. Macro Mode provides good close-up focus, while Portrait Mode provides good focus on the face of the subject. |
| Shutter- is the piece inside the digital camera that blocks light from reaching the image sensor until the photographer presses the shutter button. The shutter then opens, allowing light to pass through the lens and strike the image sensor, recording the photograph. |
| Shutter Speed- is the amount of time the digital camera's shutter remains open when capturing a photograph. The shutter is the piece of the digital camera that opens to allow light to reach the image sensor when the photographer presses the shutter button. Shutter speed usually is measured in fractions of a second, such as 1/1000th of a second. Longer shutter speeds are required for low-light photos. With the shutter open for a longer amount of time, more light can strike the image sensor to record the photo. Shorter shutter speeds are required for photos containing fast-moving subjects, thereby avoiding blurry photos. |
| Smart Media- is an obsolete type of flash memory card used in older digital cameras to store data about images. No new digital cameras that support SmartMedia cards have appeared since around 2003, and the SM cards are no longer manufactured. |
| T |
| Telephoto- refers to a lens or a digital camera with the capability to shoot photos at a closer field of view than normal human vision. Telephoto and zoom are terms often used interchangeably with digital cameras. |
| TIFF- short for Tagged Image File Format, is a type of formatting used to store digital photo files. TIFF uses only a slight compression to reduce the file size. TIFF isn't available on many beginner-level digital cameras. TIFF files do not lose image file information when undergoing the compression, meaning they take up a lot of space on a memory card, but they also don't lose image quality. |
| U |
| Ultra Compact- a beginner-level model that is extremely thin and usually controls all settings for shooting the photograph automatically, such as deciding whether to fire the flash or increase the shutter speed. Ultra compact models usually are less than 1 inch in thickness, and usually are among the most affordable types of digital cameras. |
| USB- short for Universal Serial Bus, is the most common standard for connecting a digital camera to a computer for transferal of photographs. With newer operating systems and cameras, the computer should automatically find the digital camera with a USB connection. The USB 2.0 standard allows for 480 megabits per second data transfer, easily fast enough for downloading photographs for beginner- and intermediate-level digital cameras. USB 3.0 will allow for even faster connections. |
| V |
| Viewfinder- is the small window at the top and back of the camera that you use to frame your photograph. Some cameras contain a traditional viewfinder, and some don't. Those without a viewfinder use the "live" view on an LCD, or liquid crystal display, to frame the photos. |
| W |
| White Balance- is the method by which digital cameras adjust the colors of a scene to accurately represent them. Because different sources of light -- such as a candle versus sunlight -- emit different colors of light, it's important for the digital camera to adjust its color scheme to match human vision, which can interpret all white objects as white, no matter what color of light they're reflecting. Think of white balance as the base line for creating colors using a digital camera. |
| Wide Angle- refers to a lens or a digital camera with the capability to shoot photos with a wider field of view than normal human vision. If the digital camera lens has a 35mm film camera equivalent measurement of less than 35mm, it's considered a wide-angle capability. A measurement of about 50mm is considered to be similar to human vision. |