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Canon Repairs - Imaging terms
Category: Electronics and Engineering > Canon camera and imaging terms
Date & country: 28/01/2011, UK
Words: 43


A-D Converter
The A-D Converter converts the analog signal that is emitted from the image sensor into a digital signal.

Acquire
To import digital image files into a software application. The term is often applied differently within different types of software. Users of Canon PowerShot cameras enjoy the easy-to-use and highly advanced ImageBrowser (Mac) and ZoomBrowser (PC) softwares.

Advanced Photo System
A new standard in consumer photography developed by Canon and four other System Developing Companies. It is based on a new film format and innovative film, camera and photofinishing technologies to provide the user simple loading, easy flexibility on print sizes and improved photo quality.

Angle of view
To produce a quality image there is a maximum acceptance angle of a lens that must be adhered to.

Aperture
The lens opening, which permits light to expose the CCD on a digital camera or film (in a traditional camera). The aperture size is either fixed or adjustable, and is calibrated in F-Stop numbers; the larger the number, the smaller the lens opening.

Area CCD
A square or rectangular CCD that can capture an entire image at once, which is essential for dynamic subjects and flash photography.

Aspherical surface
A lens surface that possesses more than one radius of curvature. The aspherical elements compensate for the multitude of lens aberrations common in simpler lens designs.

Autofocus TTL (through-the-lens)
Allows the camera to automatically focus through the lens, rather than by moving the lens back and forth manually. See also TTL.

Averaging
a.k.a. matrix metering or segmented metering. This type of system takes a light reading from many different areas of the frame. The microprocessor then calculates this information into a composite reading that takes into account the differences within the frame.

Bit
A bit, which stands for binary digit, is the smallest unit of digital information. Eight bits equals one byte. Digital images are often described by the number of bits used to represent each pixel. i.e. a 1-bit image is monochrome; an 8-bit image supports 256 colours or grayscales; while 24 or 32-bit supports true colour.

Bitmap
A method of storing digital information that maps an image pixel out, bit by bit. The density of the pixels determines how sharp the image resolution will be. Most image files are bit mapped. This type of file gives you the 'jaggies,' stair-stepped edges that become apparent when you zoom in. Bitmap images are compatible with all types of computers...

BMP
The bit-mapped file format used by Microsoft Windows. The BMP format supports RGB, indexed-color, grayscale, and Bitmap color modes.

Bracketing
This is an excellent method of coming to an understanding of the f/stop function. It is a technique in which takes a subject and takes a number of pictures from the same viewpoint at differing levels of exposure. Half or one f/stop (+/-) differences are usually selected depending on the subject.

CCD
Charge-coupled device. The image sensor that separates the spectrum of color into red, green and blue for digital processing by the camera. In digital cameras both Area and Linear CCDs are used. A CCD captures only black-and-white images. The image is passed through red, green and blue filters in order to capture color.

Center-Weighted
A method of determining the correct exposure for a photograph which gives more importance to the light meter reading at the center of the frame than to the peripheral areas. This method is often criticized for being too limiting to the photographer. The PowerShot S10, S20 and S100 all utilize a 3-point focal system that frees you from having to kee...

CMOS
Complementary Metal Oxide Semiconductor. A type of semiconductor that has been, until the EOS D30, widely unavailable for digital cameras. CMOS semiconductors use two circuits, negative and positive polarity circuits. Because only one of the circuits can be on at once, CMOS chips are less energy consuming than other chips that utilize simply one ty...

CMY
Cyan, Magenta and Yellow. The three colors used to make all other colors. Like CMYK, CMY is used in printing to create the colors seen in a print.

CMYK
a.k.a. Cyan, Magenta, Yellow, BlacK. The color model in which all colors are described as combinations of these four colors. Most color printers, ink-jet, laser, dye-sublimation, thermal, and crayon printers use these as their printer colors. One of the biggest challenges of desktop publishing is color matching because the conversion from RGB to CM...

Compact Flash Card
A digital image storing mechanism that is increasing in popularity and thus functionality. Flash memory is a safe, highly reliable form of storage that doesn't need power to hold the images after they are saved. It won't erase the images unless the user chooses to do so.

Complimentary color
If two colors, combined in the proper proportion form white light, then they are complimentary colors.

Compression
The compression of digital files in a format that requires less storage space. Compression techniques are distinguished from each other by whether they remove detail and color from the image. Lossless techniques compress image data without removing detail; lossy techniques compress images by removing some detail. Joint Photographic Experts Group (J...

Contrast
The difference between elements in a photograph. Contrast can include the difference between light and dark areas, or a marked difference in colors.

Dark Current
a.k.a. noise, dark noise. Pixels collect signal-charges in the absence of light over time, which can vary from pixel to pixel, and the result is known as dark current. PowerShot digital cameras reduce or eliminate dark current before a picture is captured.

Depth-of-field
The zone of in-focus elements, from front to back. Another way to put this is the range of distance that is acceptably sharp within a photograph. Depth-of field varies inversely with the aperture opening. In other words, a wide-open lens with an aperture of f/1.8 has little depth of field; if stopped down to f/16, almost everything from front to ba...

Developer
A chemical solution that changes invisible images exposed on light-sensitive film or paper into a visible image. Utilized in traditional camera film processing.

Diaphragm
The adjustable aperture of the lens. It restricts the amount of light allowed into the camera. This term can also be applied to shutter types, i.e. iris diaphragm shutter, which is a set of interposing leaves, which open and close at a variable rate to produce a between-the-lens shutter.

Digital Print Order Format (DPOF)
Digital Print Order Format (DPOF) is a standard format control file that is stored in the digital still camera's removable memory card, which specifies which image files should be printed, and the number of copies.

Digital Zoom
Unlike an optical zoom, the digital zoom takes the central portion of the high-resolution sensor's image to achieve the effect of a zoom. This means that the existing data is not enhanced or added to, merely displayed at a lower resolution, thereby giving an illusion of an enlarged image. All PowerShot cameras utilize the superior optical zoom, whi...

Dynamic range
The ability of the camera's CCD to capture a full range of shadows and highlights.

EF Lenses
Renowned for ultra fast, ultra quiet, precision autofocus. Each Canon EF lens has its own microprocessor controlled focusing motor for optimum performance. Many utilize Canon's exclusive Ultrasonic Motor technology.

Export
The act of sending a file out through a specialized mini-application or plug-in so as to print or compress it. The term is also used to describe the action of saving the data to a specialized file format, i.e. JPEG, or GIF89a.

Exposure
Exposure explains how light acts on a photographic material. The lens opening controls light intensity, while the duration is controlled by the shutter speed. A camera with autoexposure can automatically control the exposure. The same principle works with digital cameras where film is replaced by the CCD.

Exposure Compensation
A system that allows "dialing-in" or adding or subtracting evaluation values (EV) for a given image. Compensating involves deciding whether or not the meter reading is under or over exposing and correcting the error. This method allows bringing out details in dark zones or lessening the intensity of bright zones, raising image quality.

F-stop
The number assigned to a particular lens aperture (or opening) size.

File format
The way an image is saved to a digital camera's memory. The . JPEG format that PowerShot cameras store digital images as is fast becoming an industry standard.

Film
A piece of plastic with a light sensitive mixture spread on it.

Film processing
The process where chemicals remove the unexposed silver on the film, then fix or stop the developing process and stop the negative's sensitivity to light. Now with PowerShot digital cameras, you are freed from the expense of film buying and processing.

Film speed
The film's sensitivity to light. For example, an ISO 100 film requires twice as much light as an ISO 200 film.

Flash
An electronic device that produces a burst of light the consumer can use to produce more exposure on the film.

Focal length
The distance from the rear model plane of a lens to the focus when the lens is focused at the infinity position.

Focus
To adjust the distance between the lens and an image to make the image as sharp as possible.

Fringing
This occurs when a digital image is artificially sharpened. The term usually refers to a white fringe that is apparent on the edges of objects in the picture. Fringing can also occur as a result of compression.

Linear CCD
a.k.a. scanner-type CCD, these sensors are long and thin, and capture an image by recording a vast number of individual "exposures" while scanning across the picture frame. These are best suited for still subjects and continuous illumination.