Faster - Rapid. Movie or video with a frequency of 32 to 200 frames per second. Professional video

Accelerated (rapid) filming, in frequencyexceeding the standard (24 fps), is used to create the effect of slow motion, which is in demand in the projection of films, television, computer games, scientific cinema. It is used to capture sports events, to reproduce the movement of the elements of the layout or natural phenomena according to the established time scale. The screen demonstrates an imaginary slowdown in the rate of the phenomena taken, and at the same time the viewer is given the opportunity to consider the intermediate phases of the processes and poorly distinguishable details.

Features accelerated shooting

Types of shooting:

• accelerated, or rapid shooting (32-200 fps) is carried out by means of standard equipment with a grab mechanism and intermittent film movement;
• more high-speed shooting with a frequency of 200-10 000 fpsIt is provided by continuous uniform motion of the film using optical and electronic methods of light manipulation. Accelerated shooting is carried out from the hands of a moving vehicle with the help of professional or ordinary amateur equipment with the extended frequency range necessary for image stability.

Filming technologies remain almost unchanged.since 1955, the creation of an electronic shutter becomes an exception, although the image is currently fixed not on film, but on a sequence of digital matrices, thanks to which a frame rate of 100 million per second is provided.

The degree of acceleration is limited by the possibilitiescamera, its design and dynamics. For amateur equipment characteristic accelerated shooting - 64-72 fps, for professional - 360-600 fps. Modern cameras are able to provide a frequency of 200 fps with its gradual increase in order to obtain a special effect of increasing speed. If more acceleration is required, then they resort to frame manipulation on film.

Frame frequency

There are various types of filming in the scientific andapplied cinematography, in particular for the study of transient phenomena and processes. One of them is high-speed or rapid-shooting, with a frequency of more than 250 frames per second, which allows you to shoot processes that are inaccessible to the perception of the human eye due to the short duration or high speed of the phenomena.

The number of objects of study can include:

• movements of living beings: the frame rate is from 100 to 300 fps, the shutter speed is 1/1000;
• the functioning of mechanisms (1-10000 fps);
• destruction and explosions (10-100 thousand f / s);
• shock waves of gases (100 thousand - 1 million c / s);
• electrical discharges (10-100 million c / s) and the like.

Technique

Due to the variety of conditions, a wide rangetechnical means and variety of frequencies, professional video shooting of high quality objects is possible. In addition to standard image processing mechanisms, high-tech equipment also includes optical accelerators, high-speed gates, electronic and optical converters.

High-speed photography is usually carried out by means of pulsed light sources (gas-discharge lamps, explosive light sources, spark gaps with an air interval).

Chronophotography - intermediate between photos andfilming a method of capturing successive phases of phenomena using a rotating slotted shutter. The resulting images are layered on each other and combined into a single tape. The method is used for continuous movement of the object of observation. Unique effects provides an open lens with pulsed illumination.

Ways to high-speed filming

1. Imprinting on intermittently moving film is carried out at a frequency of 600 fps using a mechanical film transport system.
2. More accelerated shooting at a frequency of 1000 fps is realized using pneumatic devices or with film mobility due to the elasticity of the loops, which are formed behind the film's channels.
3. Moving photosensitive materials are used to achieve higher frequencies.

The effect of sharp shots of successive transformations is possible when the film is displaced relative to the object in the following ways.

Electronic commutation

The method by which the slit seals cut offlimited time points for frame exposure. For the shortest period of time, the frame displacement relative to the optical image does not exceed the permissible unsharpness of the negative. Intermittent illumination with pulse flashes (10–7 fractions of a second) or a shutter similar to the shutter located in front of the frame connector will be required, but instead of a cutout there may be a miniature slot (one or more).

Optical switching

If accelerated shooting assumes stillimage relative to the uniform motion of the film, it is necessary to neutralize the displacement of the light-sensitive material relative to the image in the frame exposure interval by moving the optical system reflecting the light, acting with speed and in the direction of the film.

For the implementation of optical compensation fitmirror polyhedron, glass plate or prism in motion. The size and position of the optical element must ensure that the linear displacement of the frame. The film should be located on the surface of the polyhedron in a special film channel. The method is used for low volume processes.

The limit of frequency increase during electro-switching is limited by the possibility of reducing the interval between flashes, and at optical, by the speed of rotation of the shutter disk and its diameter.

Projection slowdown

For visual viewing on the screen, slow motion is applied, which is possible both with increasing the frequency of filming and when slowing down the motion of the film in the projector.

The disadvantage of the method is visiblediscontinuity, and some high-speed processes generally fall out of sight, hiding between the footage taken during the shooting. If the slowdown is more than 1 fps, the image demonstration resembles a slide show. Therefore, the optional slowdown is often replaced with an accelerated shooting.

Modern filming techniques

1. Modern cameras are equipped with an electronic systemstabilization, but still high-quality accelerated shooting is created using a support of adjustable length, "monopod" to ensure image stability without jitter.
2. Vertical objects and sides of the frame should be parallel.
3. Such video tricks as alternationclose-ups with small and medium are considered good style. Overuse of the zooming system tires the viewer, so it’s better to stop recording sometimes, transfer the shooting to the required scale and then continue.
4. The optimum duration for perception is considered to be a plot of about 5 seconds, a maximum of 12 to preserve the liveliness and dynamism of the footage.
5. Setting the white balance in an artificially lit room is recommended to be done manually.
6. The horizon line is not the last characteristicprofessional video is different: it should be at the level of the viewfinder centerline or slightly higher. Scenes in which the upper part of the frame is occupied by 2/3 of the sky space are perceived with tension.
7. To make the frame size medium and large scale in front of the lens, you can place any object, gently creating an idea of ​​the depth and scale of the image.
8. When choosing the angle shooting should be considereddifferent perspectives, going beyond stereotypes, for example, to show an object from the audience and “judges”, as well as through the eyes of an outsider. And each such step for the operator is a new stage in his mastery and a new discovery that raises his level.

Следует также упомянуть профессиональную этику:During large events there are not so many advantageous positions that are suitable for a successful shooting, so you should take care of all the necessary conditions in advance.