Terms for digital cameras
This is a list of some of the main terms for using a digital camera
- Pixels: Are used in digital imaging and represent the smallest piece of information in an image. Pixels are tiny and one dot on an image is made up of many pixels. Each pixel can be represented by a different colour and can have three or four component colours.
- Megapixels: Is a measurement of digital photo quality and one megapixel contains one million pixels. A 1600×1200 pixel image size is a common size and is said to have “1.9 megapixels” (1600×1200 = 1,920,000)
- A 5 Megapixel digital camera: A camera capable of shooting an image measuring five million pixels in size.
- Pixel Count: The amount of pixels that an image contains is called the pixel count. The clarity and sharpness of an image will look better with more pixels.
- PPI: Or pixels per inch”, is a term used to describe an element in picture quality. It is a measure of the amount of pixels to be printed within a specific area. If the number of pixels per inch that is displayed is higher the better the image will be to the human eye.
- Aperture: In optical terms an aperture is an opening or hole through which light is admitted. This opening behind the lens permits light to travel to the digital camera’s interior where the sensor is located.
- Digital Camera Memory: Digital images or photographs are stored in a location called memory. This is an electronic storage space built into your digital cameras for the purpose of storing pictures usually in the form of Secure Digital Cards, Compact Flash Cards, SmartMedia Cards, XD Cards. In general the sizes of a digital camera memory are 64 MB, 128 MB, 256 MB, 512 MB, and 1 GIG.
- Digital zoom: Is obtained by focusing in on a portion of an image and enlarging it with a decrease in a cameras apparent angle of view. Although it results in a loss of picture quality it is a way the digital camera can zoom in using electronics and no physical adjustment.
- Optical Zoom: As opposed to digital zoom, is the ability of a lens to change its focal length and magnify an image physically using an assembly of lens elements. It does not alter the quality of the recorded digital image and is a better option than digital zoom.
- JPEG: The perfect file format used for compact storage of groups of pixels in a photograph. To reduce the picture size this ratio was fixed by the Joint Photo Experts Group. The degree of compression can be adjusted however, the higher you compression your image will result in a larger loss of picture quality.
- TIFF: Is another file format for storing images. “Tagged Image File Format” is the longer version. While there is no loss of information in this format, the resulting file sizes are also very large.
- Digital Camera Sensor: Converts light into a digital electrical signal which then produces your image for printing or viewing. It performs the role of “re-useable negative” within a digital camera.
- Shutter Speed: The common term for exposure time is the duration which the camera’s aperture is opened allowing into your camera. Longer shutter speeds leave the aperture open longer, letting more light in and resulting in more exposure.
- White Balance: To correct all the colours in an image white balance is used to account for the intensity of light an image was taken in. Because not all light is the same intensity. However modern digital cameras usually have preset values you can
- Switch on to compensate for the different light intensities which then calculate all other colours based upon this setting.
- RAW/NEF: Is the uncompressed image as shot by a digital camera before processing. Raw/NEF image files are sometimes called digital negatives Canon introduced the RAW picture format, while Nikon calls this format NEF.
Canon Ixus 870 Is
Admittedly, appearance should be one of the last factors considered by prospective camera buyers but there is no doubt that the Canon 870 is a fairly attractive piece of technical equipment. The “gold” finished version is like a piece of jewellery. Size wise it’s about the same as a packet of poker cards and that means it can fit into a handbag or pocket.
Underneath the aesthetics, the Canon 870 contains some serious camera technology. The lens is the equivalent of a 28 millimetre-112 millimetre, which provides a much wider angle of view than most of its competitors. No longer is Canon’s image-stabilisation technology only available in high-end models. It’s been incorporated into the Canon 870 and that means that sharp images can be produced without a tripod down to approximately 1/25 of a second.
Also available in the Canon 870 is automatic face detection. This works nicely and usually appears able to detect a face even in part-profile. A face self-timer function, although a bit gimmicky waits until you join the group before taking the photo. Nineteen scene modes have been added, including a 30fps VGA movie mode and a nifty macro setting.
Boasting Canon’s DIGIC 4 processing technology, the Canon 870 provides less noise at the top end of ISO settings though at 1600 there is still a lot of noise but still not bad for this class of camera.
Featuring an 28mm wide-angel lens, the Canon Ixus 870 IS takes great photos of beautiful landscapes and great group shots. Viewing your favorite photos has never been so good with the awesome 3.0 inch PureColor LCD screen.
It’s not a “serious” Canon Digital camera in the usual sense and no one is going to mistake the Canon 870 for one. For example, you won’t find an optical viewfinder or manual mode. But no biggie if all you want are fabulous photos, then this camera won’t disappoint.