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Thumbnail graphics displayed on the computer screen that locate files or applications. Clicking on them using the mouse to open a file or start-up a program.
Software program that may be used to view, store, catalogue and enhance digital images.
Term that describes using a computer program to change a digital image is also known as image processing or image enhancing. A simple form of manipulation is to remove scratches and dust or to change the subject's colour.
Cameras offer different levels of image quality which is determined by lens quality and the resolution (number of pixels) delivered by the CCD. Basic cameras have VGA resolution CCDs that record images with 640x480 pixels. Next up are SVGA models that record 800x600 pixels and then the XVGA models that create pictures with over 1024x768 pixels. The latest super megapixel models go way beyond these figures – currently creating images up to 3040x2016. If you're buying the camera to take pictures for use on screen you only need to buy a VGA model, but if you demand photo quality you need at least a megapixel variety and even then the quality is only good to about 5x7inch from a normal inkjet printer.
An image sensor is a type of transducer (an electronic device that converts one type of energy to another). This particular type of transducer converts light (visual images) to electronic signals, in essence capturing images in an electronic form: pixels. Image sensors are used in digital cameras and other imaging equipment and usually consist of an arrangement of charge-coupled devices (CCD).
A technology found in some camcorders, camera lenses and binoculars to help produce a steadier image that's free from camera shake. It uses special optical designs with some lens elements floating in fluid to reduce the movement caused by our inability to hold things rigid by hand.
General name given to illumination that's produced from an electrically heated source, such as a lamp's tungsten wire filament.
The light falling on a subject.
The measurement of light falling on the subject using a meter with a 180 diffuser cone positioned over the light sensor. This type of meter reading is not affected by the subject's reflectivity so can often be more accurate.
A distant focusing point.
A camera setting that overrides the automatic focusing and sets it to infinity so that landscapes and distant subjects come out sharp regardless of where the camera would automatically have focused. This is an important option to have when shooting though glass as the focusing system can easily be fooled.
A printer that fires minute jets of ink onto paper to make up a digital photo.
Photographic material with integral processing invented by Polaroid and also developed by Kodak and Fuji. The paper holds chemicals on one border that are squeezed over the exposed surface to process the image. Original versions had the chemicals on the outside which were messy newer types have pouch that release the processing gunge on the inside so it's a dry process.
If the camera has interchangeable backs you can change a film mid-roll so you could shoot colour and black & white within seconds of each other. This is also useful if you have several users using a camera - each could have there own film back. It's also good to record specific subjects on the same roll of film. For example you're out walking and you could take flowers on one and landscapes on the other. Many medium-format cameras have the option of changing format with different backs. You could, for example shoot 6x7cm, 6x4.5cm and 35mm from the same camera using three different backs. Polaroid backs are also available for many cameras. This means you could shoot a Polaroid print and instantly check lighting, composition or exposure and then replace with the conventional film.
Many SLRs and medium-format cameras have interchangeable focusing screens. The benefit is that you can swap the standard split screen for a different pattern to suit the type of photography you are doing. The most common is a grid screen that has a grid of thin lines used to align horizontal and vertical points in the scene. This is a popular choice for architectural photographers and for copying. A plain screen is used for microscope and telescope work, and some prefer a fresnel for focusing with long telephoto lenses where the split screen version may black out.
If the camera has interchangeable lenses you have more flexibility because the lens detaches from the camera allowing it to be replaced by a different one. Most 35mm SLR cameras and many medium-format cameras have interchangeable lenses.
Having an interchangeable viewfinder increases your scope to shoot from low down using a waist-level finder or to enable program exposure using an AE head. There are also options with magnifying hoods. Many medium format cameras have this feature, but only a couple of 35mm SLRs do.
A colour negative that's made from a colour transparency so that a colour enlargement can be made using C41 products.
The world wide web a global system of computers that are connected in networks so you can access to all kinds of information from all over the world using a modem connection.
A digital picture can be enlarged in size by adding new pixels to the existing grid. Some camera and scanner software do this as the picture is processed to give higher resolution results. The fact is, interpolation increases the picture by guessing what pixels are required and uses information from the surrounding pixels to achieve this. Although the overall picture count will rise image quality can actually suffer and definition is often reduced.
A simple mathematical law that’s usually complicated by its description. The law states that light projected onto a surface is inversely proportional to the square of its distance from the source! See what I mean? Basically if you shine a light on a subject and then move it to twice the distance the subject will receive a quarter of the intensity. Similarly when you half the distance the intensity is multiplied by four.
A small red marking to one side of the lens focus scale that you use to refocus a photograph when using infrared film.
Wavelengths of invisible light that are longer than about 720nm.
A telephone connection used mostly by businesses because it allows data files to be transmitted at about twice the speed of normal telephone lines. It costs about 50 to convert a line and costs about 40 per month rental.
Used to indicate the light sensitivity of a film. Digital cameras also use the ISO rating to indicate the CCD sensitivity. The standard rating is ISO100 and as this is increased it means that faster shutter speeds can be used. When the ISO is doubled, it doubles the available shutter speed. The drawback for digital cameras is that increasing the ISO increases the amount of digital noise in an image.
This is the company that lets you connect to the Internet. Many ISPs are now free to join, some charge a monthly fee but give you lower connection charges.