Glossary of Terms

Image sensor – an array of millions of tiny light-sensitive cells designed to capture and image in a digital camera.

Image stabilization lens - a lens incorporating gyroscopic sensors that detect camera shake and send compensating information to a suspended lens element to stabilize the image and reduce blurring.

Incident light – light falling on a subject (as opposed to light reflected by it).

Infinity – a focusing point at which a lens produces a sharp image of very distant objects such as the horizon.

Infrared radiation – electromagnet radiation, having a wavelength in the range 7,200 angstrom units to 1mm, found in the electromagnetic spectrum just beyond the red end of the visible spectrum. Although invisible to the eye it can be captured on infrared film.

Ink-jet – a printing technology based upon firing microscopic drops of ink onto a receiving medium.

Instant-return mirror – an angled mirror in an SLR camera that facilitates through-the-lens viewing but flips up to expose the film or sensor while the shutter is open.

Interpolation – the process of inserting additional pixels into an image based on the values of adjacent existing pixels.

Inverse square law – this states that the illumination of a plane surface normal to a point source is inversely proportional to the square of the distance from the source to the surface. For example, when the source to surface distance is doubled, the brightness of the surface is reduced to one quarter of its former value.

ISO – International Organization for Standardization. The ISO rating of a film or sensor represents the rate at which the light-sensitive material responds to light falling upon it.