Terms starting with O
18 terms
Octabox
An eight-sided softbox whose near-circular shape produces round catchlights and even wrap-around light.
Printing, Display & OutputOffset Lithography
The dominant commercial printing process, in which ink is transferred from a plate to a rubber blanket and then to paper.
Cameras, Formats & SystemsOne-inch Type Sensor
A sensor measuring about 13.2 by 8.8 millimetres, with a crop factor near 2.7×, common in premium compacts and drones.
Optics, Lenses & FiltersOnion-ring Bokeh
Concentric rings visible inside out-of-focus highlights, caused by tooling marks on a moulded aspherical element.
Post-Processing & RetouchingOpacity
The degree to which a layer or adjustment obscures what is beneath it, expressed as a percentage.
Lighting & FlashOpen Shade
An area shielded from direct sun but open to a large expanse of sky, giving soft, even illumination.
Printing, Display & OutputOptical Brightening Agents
Fluorescent additives in paper that absorb ultraviolet light and re-emit it as blue, making the sheet look whiter.
Motion, Video & Creative TechniquesOptical Image Stabilisation
Stabilisation achieved by moving a lens group to counteract camera shake.
Sensors & Digital CaptureOptical Low-pass Filter
A birefringent layer in front of the sensor that slightly blurs the image to prevent detail finer than the pixel grid from being recorded.
Lighting & FlashOptical Slave
A sensor that fires a flash when it detects the light from another flash.
Cameras, Formats & SystemsOptical Viewfinder
A finder that shows the scene by direct optical path rather than on a screen.
Optics, Lenses & FiltersOptical Vignetting
Corner darkening caused by the lens barrel physically clipping the light cone reaching off-axis parts of the frame.
Film, Darkroom & Historic ProcessesOrange Mask
The integral orange-coloured layer in colour negative film that corrects for imperfections in its dyes.
Film, Darkroom & Historic ProcessesOrthochromatic Emulsion
A black and white emulsion sensitive to blue and green but not to red light.
Colour & Colour ManagementOut-of-gamut Colour
A colour present in an image that the destination device or space cannot reproduce.
Post-Processing & RetouchingOutput Sharpening
A final stage of sharpening tailored to the size, medium and viewing distance of the finished image.
Motion, Video & Creative TechniquesOvercranking
Running a camera faster than the intended playback rate, the traditional term for capturing slow motion.
Exposure & MeteringOverexposure
An exposure that records more light than the sensor can hold, driving the brightest tones to pure white with no recoverable detail.