Perspective princples/methods have been used to enhance the realism of cinema, and by immersing the viewer in the imge space, and by use of two main technqiues; widescreen and 3-D or stereospcic methods.
Image Aspect Ratio
An important factor for an ordinary ‘central perspective’ camera is the image aspect ratio. This refers to the rectangular shape or proportions of the image as projected onto the picture plane, expressed as a ratio of 2 integers (such as 4:3) or in decimal format (such as 1.33:1 or simply 1.33). Different aspect ratios produce distinct aesthetic effects for human viewers, and standards have varied over time. During the silent movie era, aspect ratios varied from the square 1:1 to the extreme widescreen 4:1 Polyvision. However, around 1910, motion pictures settled on the 4:3 (1.33) aspect ratio.
The next big change in aspect ratios did not occur until the 1950s, driven by the popularity of the three-projector Cinerama system with a 2.65:1 ratio. Later, other widescreen ratios gave cinematographers a broader film frame in which to compose their images.
Many different photographic systems were developed in the 1950s for widescreen movies, but one dominated: the anamorphic process, which used anamorphic or ‘Scope Aspect’ lenses to optically squeeze the (horizontal aspect) image onto an ordinary sized film-gauge frame or format (normally 36mm by 24 mm), and thus to optically capture or photograph twice the horizontal area relative to the vertical as standard “spherical” or ‘Flat Aspect’ lenses.
Anamorphic lenses are still in use today for the same purpose. One of the anamorphic formats was CinemaScope, which used a 2.35 aspect ratio. CinemaScope was used from 1953 to 1967, but after that time, changes to latter-day projection standards altered the aspect ratio from 2.35 to 2.39.
Notably, changes in the aspect ratio of anamorphic 35 mm photography are specific to the camera or projector gate size/aperture, a basic limitation for optical system design. After the “widescreen wars” of the 1950s ended, the motion-picture industry settled on 1.85 as a standard for theatrical film projection. Europe and Asia opted for 1.66 early on, although 1.85 dominates today (for both film and digital formats as projected in theatres). Certain “epic” movies still use the anamorphic aspect ratio of 2.39.
During the 1990s, high-definition video was introduced, and television adopted the 1.78 (16:9) ratio as a compromise between the theatrical standard of 1.85 and television’s 1.33, since it was not really possible to produce a traditional CRT television tube with a 1.85 aspect ratio. Until that change, nothing had been filmed in 1.78; however, today, this is the standard for high-definition video, widescreen television, and digital film formats as well.
Widescreen Movies
In terms of film gauge, 35 mm is the most commonly used standard for still and motion photography.Where film gauge refers to the approximate width of the photographic film, which can be exposed in several different ways by the camera gate to produce different optical image sizes and/or aspect ratios.
When used for vertical film pulldown, the negative typically has an aspect ratio of 1.377. However, widescreen 35 mm negative exposures are possible by using an anamorphic format. Whereby, an anamorphic lens is used on the camera and projector, producing a wider image, with an aspect ratio of about 2.39:1 (commonly referred to as 2.40:1). The image, as recorded on the negative and the print that is projected in cinema theatres, is horizontally compressed (squeezed) by a factor of 2.
One such example is CinemaScope, which was used from 1953 to 1967 for shooting widescreen films that, crucially, could be screened in theatres using existing equipment, albeit with an anamorphic lens adapter.
Cinerama is a different widescreen process that originally projected images simultaneously from three synchronised 35mm projectors onto a large, deeply curved screen. This system involved shooting with three 35 mm cameras sharing a single shutter. However, the process was later abandoned in favour of a system using a single camera and a 70mm film gauge. The latter system lost the 146-degree field of view captured by the original three-strip system, and its resolution (and immersion) was markedly lower.
VistaVision is a higher-resolution, widescreen variant of the 35 mm motion picture film format, created by Paramount Pictures in 1954. This system did not use anamorphic processes but improved image quality by orienting the 35 mm negative horizontally in the camera gate and shooting onto a larger area, yielding a finer-grained, higher-resolution image. Paramount abandoned the format in 1961, but it was later used for the first three Star Wars films and for special-effects sequences in other feature films.
A major theme that is becoming clear is that filmmakers have generally sought to produce larger, wider cinema images that, when projected on the cinema screen, take up more of the viewers’ field of view (while maintaining good image quality, clarity, and optical resolution). In this manner, spatial immersion is enhanced.This can be achieved by using anamorphic lenses, by seeking out larger film gauges, or else by alternative optical image capture orientations that allow larger images on the negative. Of course, a larger film gauge naturally allows a larger, sharper optical image to be captured on the negative.
70 MM Movies
70 mm film (or 65 mm) is a high-resolution film format. In terms of cameras, the film is 65 mm wide, supporting wide-angle images when used with appropriate lenses. In terms of projection, the original 65 mm film is transposed to 70 mm film. Certain venues continue to screen 70 mm today.
An anamorphic lens combined with 65 mm film allows extremely wide aspect ratios while still preserving image quality/resolution.This was used in the films Ben-Hur (1959) and The Hateful Eight (2015), both filmed at an aspect ratio of 2.76:1.The latter film used a 1.25x anamorphic lens to horizontally compress the image, and a corresponding magnification-reversing lens on the projector in theatres (an effect lost on narrower format television viewings).
3-D Movies
3-D films create an illusion of three-dimensional depth or spatial solidity, usually with the help of special glasses worn by viewers that use human stereoscopic or binocular vision. They have been around since 1915, but have mostly been relegated to a niche in the motion picture industry due to the costly hardware and processes required to capture, produce, and display a 3-D film.
However, 3-D films experienced a resurgence in popularity during the 1980s and 1990s, driven by IMAX high-end theatres. 3-D films also became increasingly successful throughout the 2000s, peaking with Avatar in December 2009.
Circle-Vision 360° is a film format developed by The Walt Disney Company that uses several projection screens encircling the audience, essentially a form of cylindrical perspective projected onto an internal cylindrical screen. In the Circle-Vision 360°, the screens are arranged in a circle around the audience, with small gaps between them allowing projectors to be placed above the viewers’ heads (image projection beam angled downwards). Circle-Vision 360° cameras have been mounted on the top of automobiles or in helicopters for immersive perspective travelogue scenes.
IMAX is a diverse system of high-resolution cameras, film formats, film projectors, and theatres, known in particular for very large screens with a tall aspect ratio (approximately 1.43:1 or 1.90:1), steep stadium seating, and the 1.43:1 film format. IMAX has two camera systems: firstly, the 70mm IMAX film format, and secondly, the IMAX Digital GT. Both types of camera images can be displayed on large screens measuring 18 by 24 metres (59 by 79 feet), which are typically used today with digital laser projectors.Associated theatres are often purpose-built, dome- or spherical-shaped theatres.
Sphere Theatre
The Sphere Theatre in Las Vegas is a new all-digital venue built in 2023 that seats 18,600 people and features a 116K-resolution wraparound spherical- shaped LED interior dome screen.The venue’s exterior also features 580,000 sq ft (54,000 m2) of LED displays.The sphere measures 366 feet (112 m) high and 516 feet (157 m) wide.
Digital moving images displayed on the Sphere Theatre use a special camera called the Big Sky camera with an 18K pixel sensor that measures 77.5mm x 75.6mm (3.05”by 2.98″); and the system can capture images at 120 fps and produce data at 60 gigabytes per second.The camera includes a pair of lenses (to capture content in stereoscopic 3-D) that cover this sensor’s resolution and size/size and match the screen’s size, shape, and field of view.
The curvature of the dome’s screen makes such a fisheye lens a natural geometric fit; however, it has to resolve extraordinary detail for the 16K pixels of the screen.The audience’s normal vision inside the Sphere places the most important part of the image at the bottom of the screen, because this is the most comfortable and common viewing angle. However, there is still a considerable image segment above the audience’s head, so when a typical scene is shot, the camera must be tilted at 55 degrees to capture an angle of view that fills the entire screen (ref. matching audience presented field of view), with the “centre” of the action framed on the lower edge of the lens, normally a suboptimal region for a fisheye lens whose periphery often yields poor image quality.
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