Glossary of Digital Photography Terms: Definitions

Aperture of the lens – adjustment of the “iris”, which controls the amount of light entering the lens.
Auto-focus – the selection of a point in the imaging frame upon which the auto-focus system will attempt to focus.
Depth of field (DOF) – is the distance in front of and beyond the subject that appears to be in focus.
Film speed – is the measure of a photographic film’s sensitivity to light.
Image noise or Film grain – is a random, usually unwanted, fluctuation of pixel values in an image.
ISO – on film cameras it’s an indicator of the selected film speed on film cameras, on digital cameras it’s an indication of the imaging chip’s light sensitivity.
Motion blur – is the apparen’t streaking of rapidly moving objects in a still image.
Shutter speed – adjustment of the speed of the shutter to control the amount of time during which the imaging medium is exposed to light per each exposure.
Photography – is the process of making pictures by means of the action of capturing light on a film.
White balance – electronic compensation for the color temperature associated with a given set of lighting conditions, ensuring that white light is registered as such on the imaging chip and therefore that the colors in the frame will appear natural.
Color balance – often refers to the modification of the color values of an image to generate the correct colors on a particular image display or printing device.
Filter – is a camera accessory, a glass or plastic disk with a metal or plastic ring frame, consisting of an optical filter (for different colors: green, blue, red, yellow) that can be inserted in the optical path.
Megapixels – millions of pixels (usually used in reference to the resolution of an image sensor).
Pixel – is a single point in a graphic image.
Optical zoom – uses the optics (lens) of the digital camera to move you closer to your subject.
Digital zoom – simply uses the existing image and enlarges it digitally.
Blur – generally refers to the appearance of an unfocused image.
Gaussian blur – is an effect used to reduce image noise and reduce detail levels.
Red-eye effect – is the common appearance of red eyes on photographs taken with a photographic flash when the flash is too close to the lens (like in compact cameras).
Multiple exposure – is an exposure in which the sensitivity to light is reduced and then increased at least once during the total exposure time.
Tripod – is a three-legged stand for a camera, used to stabilize and elevate the camera.
Vignetting – refers to a reduction in image brightness in the image periphery compared to the image center.
Spherical aberration – is the term for an optical fault caused by the spherical form of a lense that produces different focus points along the axis for central and marginal rays.
Curvature of field – optical defect that causes points on an object plane perpendicular to the lens axis to focus on a curved surface rather than a plane.
Astigmatism – aberration in which rays of light from a single point of an object (which is not on the axis of a lense) fail to meet in a single focus thus causing the image of a point to be drawn out into two sharp lines, one radial to the optical axis and another perpendicular to this line, in two different planes near the curvature of field.
Coma – optical defect that causes the image of an off-axis point of light to appear as a comet-shaped blur of light.
Distortion – an rectangle may appear as a barrel or pin cushion-shaped object.
Chromatic aberration – aberration caused by light rays of different wavelengths coming to focus at different distances from the lense.
Aspherical lens – a lens whose curved surface does not conform to the shape of a sphere; because a spherical surface lens has difficulty in correcting distortion in ultra-wideangle lenses or coma in large-aperture lenses brought about by spherical aberration, an aspherical lens is used.
Aspect Ratio – the ratio of width to height in photographic prints – 2:3 in 35 mm pictures to produce photographs most commonly measuring 3.5 x 5 inches or 4 x 6 inches.



I started photography as a hobby in 2005, during college. My passion slowly became a more important part of my life since 2008. Because of using a combination of my photographic knowledge, with those of internet marketing, I like to call myself a "photomarketer".

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