movie camera that allows (with the addition of a monitor) the director to see approximately the same view as the camera operator, and thus ensure that the film is being shot and framed as desired. This is done by using a small charge-coupled device (CCD) (similar to ones in consumer camcorders) inside the viewfinder. On modern film cameras, the assist is fed off a beam splitter, which splits the beam between the optical viewfinder and the video tap. The light enters through the lens, and hits the rotating mirror shutter, which bounces the light to the horizontal ground glass. The beam splitter is directly over the ground glass and turns the light again 90 degrees, and projects it onto the chip of the video assist camera—through its own lens system. The chip, together with its electronics, lens system and mounting hardware, is the video tap, and was commonly called video assist until the video assist industry grew large. On steadicam and remote head or crane operation, the viewfinder and beam splitter is often removed because it's not needed. Then the full image is projected onto the video tap, making the image twice as bright, and hence better quality (lower noise). In these cases, even the camera operator uses a video monitor to operate the camera. Though the quality of the film video assist feed can vary greatly based on both the camera and the assist, it is always used as a guide and nothing more. Because the assist has its own controls for exposure, contrast, focus and color correction, it is not possible to use it to learn anything more than the frame lines. The video assist camera is usually significantly lower in resolution than the film camera as well, so critical focus is still usually determined by distance from the lens to the subject via a tape measure. After the revolution of the electronic HD cameras, film camera manufacturers added HD resolution video taps to their cameras. Video assist on electronic cameras While the traditional video tap no longer applies to modern CCD based cameras, large-scale productions with HD cameras still use video assist in its wider meaning. In this case, the video signal is fed from the camera's own video output, and is a significantly better quality than the original video tap technology. HD cameras can output HD-SDI video signals, which, when presented on a high-grade calibrated monitor,