Photography terms starting with O

Octabox Lighting & Flash cm An eight-sided softbox whose near-circular shape produces round catchlights and even wrap-around light.

Offset Lithography Printing, Display & Output lpi The dominant commercial printing process, in which ink is transferred from a plate to a rubber blanket and then to paper.

One-inch Type Sensor Cameras, Formats & Systems mm A sensor measuring about 13.2 by 8.8 millimetres, with a crop factor near 2.7×, common in premium compacts and drones. Crop factor ≈ 2.7

Onion-ring Bokeh Optics, Lenses & Filters Concentric rings visible inside out-of-focus highlights, caused by tooling marks on a moulded aspherical element.

Opacity Post-Processing & Retouching % The degree to which a layer or adjustment obscures what is beneath it, expressed as a percentage.

Open Shade Lighting & Flash An area shielded from direct sun but open to a large expanse of sky, giving soft, even illumination.

Optical Brightening Agents Printing, Display & Output Fluorescent additives in paper that absorb ultraviolet light and re-emit it as blue, making the sheet look whiter.

Optical Image Stabilisation Motion, Video & Creative Techniques stops Stabilisation achieved by moving a lens group to counteract camera shake.

Optical Low-pass Filter Sensors & Digital Capture A birefringent layer in front of the sensor that slightly blurs the image to prevent detail finer than the pixel grid from being recorded.

Optical Slave Lighting & Flash m (range) A sensor that fires a flash when it detects the light from another flash.

Optical Viewfinder Cameras, Formats & Systems A finder that shows the scene by direct optical path rather than on a screen.

Optical Vignetting Optics, Lenses & Filters stops (EV) Corner darkening caused by the lens barrel physically clipping the light cone reaching off-axis parts of the frame.

Orange Mask Film, Darkroom & Historic Processes The integral orange-coloured layer in colour negative film that corrects for imperfections in its dyes.

Orthochromatic Emulsion Film, Darkroom & Historic Processes nm A black and white emulsion sensitive to blue and green but not to red light.

Out-of-gamut Colour Colour & Colour Management A colour present in an image that the destination device or space cannot reproduce.

Output Sharpening Post-Processing & Retouching % A final stage of sharpening tailored to the size, medium and viewing distance of the finished image.

Overcranking Motion, Video & Creative Techniques fps Running a camera faster than the intended playback rate, the traditional term for capturing slow motion.

Overexposure Exposure & Metering stops (EV) An exposure that records more light than the sensor can hold, driving the brightest tones to pure white with no recoverable detail.

Terms starting with O