Fast shooting - rapid. Film or video shooting at a frequency of 32 to 200 frames per second. Professional video filming

2024 Author: Leah Sherlock | [email protected]. Last modified: 2023-12-17 05:25

Speed-up (rapid) filming, which exceeds the standard (24 fps) in frequency, is used to create the effect of slow motion, which is in demand in the projection of films, television, computer games, and scientific cinema. It is used to capture sporting events, to reproduce the movement of layout elements or natural phenomena according to a set time scale. The screen shows an imaginary slowdown in the pace of the filmed phenomena, while the viewer is given the opportunity to consider the intermediate phases of processes and poorly distinguishable details.

Slow motion features

Shooting types:

• accelerated, or rapid shooting (32-200 fps) is carried out using standard equipment with a clamshell mechanism and intermittent film movement;
• faster shooting with a frequency of 200-10,000 fps is provided by continuous uniform film movement using optical and electronic light manipulation methods. Accelerated filming is carried out from the hands of a moving vehicle using a professional or ordinary amateurequipment with an extended frequency range, necessary for image stability.

Film technology has remained almost unchanged since 1955, except for the creation of an electronic shutter, although the image is now captured 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 capabilities of the camera, its design and dynamics. For amateur equipment, accelerated shooting is typical - 64-72 fps, for professional equipment - 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 the manipulation of frames on the film.

Frame rate

There are various types of filming in scientific and applied cinematography, in particular for the study of fast-flowing 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 capture processes that are inaccessible to the perception of the human eye due to the short duration or high speed of phenomena.

The number of objects of study can include:

• movement of living creatures: frame rate is from 100 to 300 fps, shutter speed is 1/1000;
• functioning mechanisms (1-10000 fps);
• destruction and explosions (10-100k fps);
• shock waves of gases (100 thousand - 1million fps);
• electric discharges (10-100 million fps) and the like.

Techniques

Due to a variety of conditions, a wide range of technical means and a variety of frequencies, professional video shooting of high quality objects is possible. High-tech equipment, in addition to standard image processing mechanisms, also uses optical accelerators, fast shutters, electronic and optical converters.

High-speed photography is usually done with pulsed light sources (discharge lamps, explosive light sources, air gap spark gaps).

Chronophotography is an intermediate between photography and filming a way of capturing the successive phases of phenomena using a rotating slit shutter. The resulting images are layered on top of each other and combined into a single tape. The method is used for continuous movement of the object of observation. Unique effects are provided by an open lens with pulsed illumination.

High-speed filming methods

1. The intermittent motion film is imprinted at 600 fps using a mechanical film transport system.
2. More faster shooting at 1000 fps is realized using pneumatic devices or with film mobility due to the elasticity of the loops that form behind the film channels.
3. Moving photosensitive sensors are used to achieve higher frequenciesmaterials.

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

Electronic switching

A method in which slit obturators cut off limited time points for exposing a frame. For the shortest period of time, the shift of the frame relative to the optical image does not exceed the permissible blur of the negative. You will need intermittent lighting with pulsed flashes (lasting 10-7 fractions of a second) or a shutter located in front of the frame connector like a shutter, but instead of a cutout there may be a miniature slot (one or more).

Optical switching

If fast shooting involves a still image relative to the uniform movement of the film, it is necessary to neutralize the displacement of the light-receptive material relative to the image in the exposure interval of the frame by moving the light-reflecting optical system, acting at the speed and in the direction of the film movement.

To implement optical compensation, a mirror polyhedron, a glass plate or a prism in motion are suitable. The size and position of the optical element must ensure that the linear displacement matches the frame movement. The film must be placed on the surface of the polyhedron in a special film channel. The method is used for low-volume processes.

Frequency increase limit for electrical switching is limited by the possibility of shortening the intervalbetween flashes, and with optical - the speed of rotation of the shutter disk and its diameter.

Projection slowdown

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

The disadvantage of the method is the visible discontinuity, and some high-speed processes generally fall out of sight, hiding between the captured frames during the shooting. If the slowdown is more than 1 fps, the image will be displayed like a slide show. Therefore, optional slow motion is often replaced by fast motion.

Modern filmmaking techniques

1. Modern cameras are equipped with an electronic stabilization system, but still high-quality fast-paced footage is created using an adjustable-length support, a "monopod", to ensure image stability without shaking.
2. Vertical objects and frame sides should be parallel.
3. Such video techniques as alternating close-ups with small and medium shots are considered good style. Overuse of the zoom system will tire the viewer, so sometimes it's best to stop recording, zoom in and then continue.
4. The most optimal duration for perception is considered to be a plot of about 5 seconds, a maximum of 12 to maintain liveliness and dynamism of the footage.
5. Setting the white balance in an artificially lit room is recommended to be done manually.
6. LineThe horizon is not the last characteristic that distinguishes professional video shooting: it should be at the level of the center line of the viewfinder or a little higher. Scenes in which the top of the frame is 2/3 of the sky are perceived with tension.
7. To give volume to medium and large shots, you can place an object in front of the lens that unobtrusively creates an idea of the depth and scale of the image.



8. When choosing a shooting angle, one should consider various perspectives, going beyond stereotypes, for example, to show the object from the side of the audience and "judges", as well as through the eyes of an outside observer. And each such step for the operator is a new round in his skill and a new discovery that raises his level.

Professional ethics should also be mentioned: during big events, there are not many vantage points that are suitable for successful shooting, so it is worth taking care of all the necessary conditions in advance.