| Overlap | Two shots that look like they have been taken at the same time on two camcorders |
| over/under | shots that cross the surface boundary i.e the camera lens is half-in and half-out of the water showing subjects above and below |
| Outer Glow | Add glows that emanate from the outside or inside edges of the layer's content. |
| O-ring | The rubber ring that seals underwater camera equipment. |
| Orientation Sensor | A special sensor in some cameras that "knows" when you turn the camera in portrait orientation to take a vertical shot and "tells" the camera to display it that way later when viewed on the TV screen during playback |
| Options bar | a menu with context sensitive commands for the active tool that appears (by default) screen top left below the main menu |
| Optimize | The process of fine-tuning the file size and display quality of an image or image slice destined for the web |
| Optical Zoom | Optical zoom is a camera feature where the lens system physically changes focal length to zoom in on distant subjects |
| Opaque | Not transparent, among other meanings including to “block out” a specific area of an image or film. |
| Opacity | Used to specify how transparent a layer should be, either on its own or in regard to other layers. When color-separating artwork, you can use the Opacity Slide to "pull" more color from the image, thus making color separating artwork easier. |
| Oilify | Applies an oil painting effect to the bitmap. |
| Ohm | The unit of electrical resistance. A resistance of 1 Ohm will pass a current of 1 Amp when a voltage of 1 Volt is applied across it. |
| ODR | Output Device Resolution. The number of ink dots per inch of paper produced by the printer |
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