Slow motion

Typically this style is achieved when each film frame is captured at a rate much faster than it will be played back. When replayed at normal speed, time appears to be moving more slowly. The technical term for slow motion is overcranking which refers to the concept of cranking a handcranked camera at a faster rate than normal (i.e. faster than 24 frames per second). Slow motion can also be achieved by playing normally recorded footage at a slower speed. This technique is more often applied to video subjected to instant replay, than to film. High-speed photography is a more sophisticated technique that uses specialized equipment to record fast phenomena, usually for scientific applications.

Slow motion is ubiquitous in modern filmmaking. It is used by a diverse range of directors to achieve diverse effects. Some classic subjects of slow motion include:

• Athletic activities of all kinds, to demonstrate skill and style.
• To recapture a key moment in an athletic game, typically shown as a replay.
• Natural phenomena, such as a drop of water hitting a glass.

Slow motion can also be used for artistic effect, to create a romantic or suspenseful aura or to stress a moment in time. Vsevolod Pudovkin, for instance, used slow motion in a suicide scene in The Deserter, in which a man jumping into a river seems sucked down by the slowly splashing waves. Another example is Face/Off, in which John Woo used the same technique in the movements of a flock of flying pigeons. The Matrix made a distinct success in applying the effect into action scenes through the use of multiple cameras, as well as mixing slow-motion with live action in other scenes. Japanese director Akira Kurosawa was a pioneer using this technique in his 1954 movie Seven Samurai. American director Sam Peckinpah was another classic lover of the use of slow motion. The technique is especially associated with explosion effect shots and underwater footage.^{[citation needed]}

The opposite of slow motion is fast motion. Cinematographers refer to fast motion as undercranking since it was originally achieved by cranking a handcranked camera slower than normal. It is often used for comic effect, time lapse or occasional stylistic effect.

The concept of slow motion may have existed before the invention of the motion picture: the Japanese theatrical form Noh employs very slow movements.

How slow motion works

There are two ways in which slow motion can be achieved in modern cinematography. Both involve a camera and a projector. A projector refers to a classical film projector in a movie theater, but the same basic rules apply to a television screen and any other device that displays consecutive images at a constant frame rate.

Overcranking

For the purposes of making the above illustration readable a projection speed of 10 frames per second (frame/s) has been selected, in fact film is usually projected at 24 frame/s making the equivalent slow overcranking is rare, but available on professional equipment.

Time stretching

Frames marked with an X must be fabricated.

The second type of slow motion is achieved during post production. This is known as time-stretching or digital slow motion. This type of slow motion is achieved by inserting new frames in between frames that have actually been photographed. The effect is similar to overcranking as the actual motion occurs over a longer time.

Since the necessary frames were never photographed, new frames must be fabricated. Sometimes the new frames are simply repeats of the preceding frames but more often they are created by interpolating between frames. (Often this interpolation is effectively a short dissolve between still frames). Many complicated algorithms exist that can track motion between frames and generate intermediate frames that appear natural and smooth. However it is understood that these methods can never achieve the clarity or smoothness of its overcranking counterpart.

Traditionally, frames were duplicated on an optical printer. True frame interpolation can only be done digitally.

Simple replication of the same frame twice is also sometimes called half-speed. This relatively primitive technique (as opposed to digital interpolation) is often visually detectable by the casual viewer. It was used in certain scenes inTarzan, the Ape Man, and critics pointed it out. Sometimes lighting limitations or editorial decisions can require it. A wide-angle shot of Roy Hobbs swinging the bat, in the climactic moments of The Natural, was printed at half-speed in order to simulate slow-motion, and the closeup that immediately followed it was true overcranked slow-motion.

A VCR may have the option of slow motion playback, sometimes at various speeds; this can be applied to any normally recorded scene. It is similar to half-speed, and is not true slow-motion, but merely longer display of each frame.

In action films

Slow motion is used widely in action films for dramatic effect, as well as the famous bullet-dodging effect, popularized by The Matrix.

Formally, this effect is referred to as speed ramping and is a process whereby the capture frame rate of the camera changes over time. For example, if in the course of 10 seconds of capture, the capture frame rate is adjusted from 60 frames per second to 24 frames per second, when played back at the standard film rate of 24 frames per second, a unique time-manipulation effect is achieved. For example, someone pushing a door open and walking out into the street would appear to start off in slow-motion, but in a few seconds later within the same shot the person would appear to walk in "realtime" (normal speed). The opposite speed-ramping is done in The Matrix when Neo re-enters the Matrix for the first time to see the Oracle. As he comes out of the warehouse "load-point", the camera zooms into Neo at normal speed but as it gets closer to Neo's face, time seems to slow down, perhaps visually accentuating Neo pausing and reflecting a moment, and perhaps alluding to future manipulation of time itself within the Matrix later on in the movie.

Slow Motion effects can be created after the original material is captured using VFX plug-ins like Twixtor(TM)developed by RE:Vision Effects http://www.revisionfx.com

In Broadcasting

Slow-motion is widely used in sport broadcasting and its origins in this domain extend right back to the earliest days of television, one example being the European Heavyweight Title in 1939 where Max Schmeling knocked out Adolf Heuser in 71 seconds.

In instant replays, slow motion reviews are now commonly used to show in detail some action (photo finish, Football (soccer) goal, ...). Generally, they are made with video servers and special controllers. The first TV slo-mo was the Ampex HS-100 disk record-player.

HS-100 at DC Video, [2],

Super 16 mm Camera

Super 16 mm

The variant called Super 16 mm, Super 16, or 16 mm Type W uses single-sprocket film, and takes advantage of the extra room for an expanded picture area of 7.41 mm by 12.52 mm with a wider aspect ratio of 1.67. Super 16 cameras are usually 16 mm cameras which have had the film gate and ground glass in the viewfinder modified for the wider frame. Since Super 16 takes up the space originally reserved for the soundtrack, films shot in this format can be enlarged by optical printing to 35 mm for projection. However, with the recent development of digital intermediate workflows, it is now possible to digitally enlarge to 35 mm with virtually no quality loss (given a high quality digital scan), or alternatively to use high-quality video equipment for the original image capture.

In 2009, German lens manufacturer Vantage introduced a series of anamorphic lenses under its HAWK brand with a 1.3x squeeze factor (as opposed to the standard 2x) specifically made for the Super 16 format. These lenses allow the entire Super 16 frame to be used for 2.35:1 widescreen photography.

Shutter speed

In still cameras, the term shutter speed represents the time that the shutter remains open when taking a photograph. Along with the aperture of the lens (also called f-number), it determines the amount of light that reaches the film or sensor. Conventionally, the exposure is measured in units of exposure value (EV), sometimes called stops, representing a halving or doubling of the exposure.

Multiple combinations of shutter speed and aperture can give the same exposure: halving the shutter speed doubles the exposure (1 EV more), while doubling the aperture (halving the number) increases the exposure by a factor of 4 (2 EV). For this reason, standard apertures differ by √2, or about 1.4. Thus an exposure with a shutter speed of 1/250 s and f/8 is the same as with 1/500 s and f/5.6, or 1/125 s and f/11.

In addition to its effect on exposure, the shutter speed changes the way movement appears in the picture. Very short shutter speeds can be used to freeze fast-moving subjects, for example at sporting events. Very long shutter speeds are used to intentionally blur a moving subject for artistic effect. Short exposure times are sometimes called "fast", and long exposure times "slow".

Adjustment to the aperture controls the depth of field, the distance range over which objects are acceptably sharp; such adjustments need to be compensated by changes in the shutter speed.

In early days of photography, available shutter speeds were not standardized, though a typical sequence might have been 1/10 s, 1/25 s, 1/50 s, 1/100 s, 1/200 s and 1/500 s. Following the adoption of a standardized way of representing aperture so that each major step exactly doubled or halved the amount of light entering the camera (f/2.8, f/4, f/5.6, f/8, f/11, f/16, etc.), a standardized 2:1 scale was adopted for shutter speed so that opening one aperture stop and reducing the shutter speed by one step resulted in the identical exposure. The agreed standards for shutter speeds are:

• 1/1000 s
• 1/500 s
• 1/250 s
• 1/125 s
• 1/60 s
• 1/30 s
• 1/15 s
• 1/8 s
• 1/4 s
• 1/2 s
• 1 s

An extended exposure can also allow photographers to catch brief flashes of light, as seen here. Exposure time 15 seconds.

With this scale, each increment roughly doubles the amount of light (longer time) or halves it (shorter time).

Camera shutters often include one or two other settings for making very long exposures:

• B (for bulb) keeps the shutter open as long as the shutter release is held.
• T (for time) keeps the shutter open until the shutter release is pressed again.

The ability of the photographer to take images without noticeable blurring by camera movement is an important parameter in the choice of slowest possible shutter speed for a handheld camera. The rough guide used by most 35 mm photographers is that the slowest shutter speed that can be used easily without much blur due to camera shake is the shutter speed numerically closest to the lens focal length. For example, for handheld use of a 35 mm camera with a 50 mm normal lens, the closest shutter speed is 1/60 s. This rule can be augmented with knowledge of the intended application for the photograph, an image intended for significant enlargement and closeup viewing would require faster shutter speeds to avoid obvious blur. Through practice and special techniques such as bracing the camera, arms, or body to minimize camera movement longer shutter speeds can be used without blur. If a shutter speed is too slow for hand holding, a camera support, usually a tripod, must be used. Image stabilization can often permit the use of shutter speeds 3–4 stops slower (exposures 8–16 times longer).

Shutter priority refers to a shooting mode used in semi-automatic cameras. It allows the photographer to choose a shutter speed setting and allow the camera to decide the correct aperture. This is sometimes referred to as Shutter Speed Priority Auto Exposure, or Tv (time value) mode.