Topic: Imaging Terminology

Aliasing

What Is Aliasing and How Does It Relate to Digital Photography? In photography aliasing is a form of distortion that occurs when two elements of the signal being processed to form a digital image become indistinguishable from one another. Aliasing often appears in an image in the form of moiré or false colouring. Many digital cameras feature a built in ‘anti-aliasing filter’ to counteract the effects of aliasing by preventing high frequencies of light from reaching the sensor. This introduces a small amount of blur to detailed areas of an image that can prevent aliasing from occurring. The image...

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Anti-Shake

What Is Anti-Shake and how Is it Used In Photography? In photography an anti-shake system compensates for unwanted movement of the camera which would otherwise blur a photograph whilst shooting, for example hand holding a camera whilst shooting in low light conditions. There are two main types of anti-shake system; Lens based anti-shake uses a moving optical element to counteract shaking. Camera based anti-shake uses a mechanism which allows the image sensor to move to compensate for unwanted movement. Anti-shake systems are also extremely popular with videographers who’s cameras do double duty as both a stills and video capture...

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Color Palette

What is a Color Palette When Talking About Photography and Image Editing? Also referred to as ‘palette’ the term ‘color palette’ describes the entire range of colors that can be rendered by a digital device such as a camera LCD or a computer monitor, or the range of colors contained within a specific image. A computer monitor may have a color palette of 16 million colors, an image on the other hand often contains a much smaller number, often 256. The term is also used to describe a collection of colors, usually displayed graphically in RGB triplets, which a...

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Light Painting

What Is Light Painting and How Is It Used in Photography? A ‘light painting’ is an image that is created by capturing a long exposure of a dark scene that contains a moving light source. By moving the light source within the scene whilst the photographic medium is being exposed the photographer is able to produce an effect which resembles the brush strokes made by an artist’s paint brush, only composed entirely of light. A classic example of a light painting is writing your name using a sparkler at a firework display. Light Paintings can be created by capturing...

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Magnetic Storage

What Is Magnetic Storage When Talking About Photography? when talking about photography magnetic storage refers to a form of storage in which information is recorded on a magnetised plate within a storage device. The data is stored by applying different levels of magnetism to different areas of a magnetic plate using a write head. This information can then be read at a later time by a read head which can measure the levels of magnetism applied to the plate. Magnetic storage is non-volatile and can be found in the hard drives which you use to store your digital images....

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Normal Lens

What Is a Normal Lens and How Is It Used When Taking Photos? A ‘normal lens’ is a Lens with a focal length approximately equal to the diagonal of the film format or of a digital camera’s image sensor. A scene viewed through a normal lens appears to have the same perspective as the way your eye sees it. Most 35mm cameras normal lenses have a focal length of approximately 50 mm. Normal lenses are extremely popular with street photographers because the perspective captured in an image shot with a normal lens will be extremely true to life, having the...

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Opacity

What Does Opacity Mean When Talking About Photography? Opacity is the measure of an objects impenetrability to electromagnetic radiation. When talking about photography the term is used to describes exactly how much an object blocks light from passing through it. An object that completely blocks light is called opaque, no light is able to pass through it. The opposite of opaque is transparent. Many opaque objects will reflect light which can be problematic when taking photos. Knowing the opacity of objects is also very important when designing lenses; lens elements despite very low opacity values will still block small...

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Optical Resolution

What Does Optical Resolution Mean When Talking About Photography and Cameras? When talking about cameras and photography the term ‘optical resolution’ describes the total resolution that a digital camera, or optical device such as a scanner is able to capture. The optical resolution is expressed in megapixels or MP, with each megapixel being a total of one million pixels. A camera with an optical resolution of 24.2MP therefore is able to record an image which contains a total of 24200000 pixels. Shot in an image ratio of 3:2 a 24.2MP image would have a resolution of 6016 x 4016...

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Optical Storage

What Is Optical Storage and how Is it Used in Photography? Optical storage is a storage medium where information is stored on a material that is able to be read optically. Information is stored by marking the optically readable material, and can then be read by shining a laser onto the previously recorded areas. Measurement of whether the light is reflected of absorbed allows a digital readout to be produced which can then be converted back into the original data. Examples of optical storage are CDs and DVDs which you might use to store digital images. Optical storage formats are...

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Optical Zoom

What does Optical Zoom mean when talking about photography? When talking about photography the term ‘optical zoom’ refers to a specific type of lens which allows a photographer to alter the magnification ratio by changing the distance between groups of optical elements within the lens. The zoom ratio of an optical zoom lens is often controlled by rotating the front portion of the lens, this manipulates a mechanism within the lens which moves elements within the lens barrel. On smaller cameras the zoom ratio may be controlled electronically using a motor. Importantly, the focus settings of a lens are...

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