Refresh rate

Tobo · ‎22.05.2024

Refresh rate

Definition

The refresh rate or frame rate is a term used in film, television and computer technology. It refers to the number of individual images per second that are projected onto a cinema screen, for example, or written onto a television screen or monitor by its electron beam. television screen or monitor through its electron beam. This is usually specified in the unit Hertz (Hz) or, equivalently, as fps (frames per second). With digital media and cinema projections, a distinction is made between the refresh rate of the film and that of the projector.

Video or moving image reproduction utilises the physiological characteristic of the human visual system that changes in the image content are mixed with the afterimage of the previous image content, which continues to exist in the millisecond range.

It is important to differentiate between frame rate and refresh rate, as they do not have to be identical. The frame rate should not fall below a value of approx. 30 frames / second in order to give the human eye a smooth image impression with moving image content. to convey a smooth image impression to the human eye in the case of moving image content.
The limit to the perception of flowing movement varies slightly from person to person. person is slightly different. The frame rate of 24 Hz that is common in today's cinema limits the moving image display, which means that objects that move at a slower, medium speed on the screen appear as jerks, moving at an unfavourable, medium speed on the screen are perceived as „jerky“. A good director knows how to avoid this, by, for example, making camera pans very slow or sufficiently fast. Recording with studio cameras or camcorders uses the interlaced method, which offers clear advantages due to the higher frame rate of 50 or 60 movement phases per second, e. g. for sports recordings.