A 3D rig is a device for mounting two cameras together to one 3D-system in order to shoot stereoscopic films and images.
To create stereoscopic depth illusion in movie or photography, two slightly different images have to be viewed at the same time, each of them presented to one eye.
In order to capture moving objects, the images have to be taken in exactly the same moment. Therefore, it is necessary to shoot with two cameras that are in sync. In addition to that the cameras have to be geometrically aligned accurately, to minimize the amount of stereoscopic errors. [1]
A 3D Rig, as a result, must provide the possibility to mount two cameras, with a horizontal offset and adjust the cameras in all possible axes. [2] For 3D moviemaking, it is also necessary that the horizontal distance between the cameras can be adjusted via remote control while shooting. It is important that the rigs have a high stability. This is to assure that they do not deform during movement, for example on a crane. Otherwise this could impact or destroy the camera alignment. [3]
In general there are two types of 3D Rigs, side-by-side rigs and mirror rigs. [4]
The least complex way to take pictures or shoot film in 3D is having two cameras mounted side-by-side. They are aligned parallel to each other, or can be angulated so that their optical axes meet at a chosen distance. In some systems the cameras are fixed to the rig body and can not be moved. More professional side-by-side-rigs, however, offer the possibility to change the interaxial distance easily.
A side-by-side rig is a proper way to do wide shots like landscape or overviews in sport broadcasting, however they cannot be used for close-ups since the minimum distance between the cameras is limited to the size of the lenses.
Side-by-side rigs are comparably easy to build and therefore cheap. [5] They also often provide bigger possible interaxial distances then mirror rigs, which can be used to create a miniaturization effect.
Side-by-side rigs cannot be used for close-ups since the minimum distance between the cameras is limited to the size of the lenses. For close-up shots though it is necessary to have smaller interaxial distances. For most shooting situations in live action film therefore mirror rigs are used.
In a mirror rig the two cameras look through a beamsplitter. One camera sees right through it. The other one captures the reflected image. One camera is placed above or below the other one at a ninety-degree angle. [6] In some rigs only one camera can be moved. This can throw the system's weight out of balance, which can cause problems when used on a camera stabilization mount (e.g. Steadicam). Others offer the possibility to move both cameras simultaneously.
The mirror rig is the one to choose for shooting live action film. “It makes the best 3D pictures, and some stereographers would say ‘the only good 3D pictures’”. [7] Because the cameras in this set-up aren’t physically in their way, the distance between the optical axes of the cameras can be smaller than the size of the lenses and even down to zero. Shots with small interaxial distances are possible, which is necessary for shooting in a classical movie style with close-up and detail shots.
Mirror rigs make telling stories with classical tools of film narration possible. For close-ups, two shots, details and most dialogue scenes, the interaxial distance has to be not more than a couple of millimeters. This is only possible with a mirror rig. [7] To simply zoom in or use long lenses to get close-up shots with a side-by-side rig leads to a bad roundness. [8]
Another advantage is, that the images can be used for the geometrical alignment of the cameras since stereoscopic errors can be seen most easily when the interaxial distance is zero.
With the mirror there is one more optical element that has to be handled and manufactured carefully, which makes these rigs usually more expensive than side-by-side rigs. "The use of mirrors makes it sensitive to dust and fast accelerations. The mirror needs to be big enough to accommodate wide angles. It requires accurate mirror placement toward the cameras; otherwise keystone artifacts will affect the images." [7] The mirror itself also takes away one f-stop [9] since the light is split up for the two cameras. Mirrors of bad quality can produce a color mismatch that has to be corrected in postproduction. In addition to that every mirror filters the light according to its polarization. This leads to brightness differences between the two images especially at reflections and transparent objects.
A camera is an optical instrument that captures images. Most cameras can capture 2D images, while some more advanced models can capture 3D images. At a basic level, most cameras consist of a sealed box, with a small hole that allows light to pass through and capture an image on a light-sensitive surface. Cameras have various mechanisms to control how light falls onto the light-sensitive surface, including lenses that focus the light and a shutter that determines the amount of time the photosensitive surface is exposed to the light.
A rangefinder camera is a camera fitted with a rangefinder, typically a split-image rangefinder: a range-finding focusing mechanism allowing the photographer to measure the subject distance and take photographs that are in sharp focus. Most varieties of rangefinder show two images of the same subject, one of which moves when a calibrated wheel is turned; when the two images coincide and fuse into one, the distance can be read off the wheel. Older, non-coupled rangefinder cameras display the focusing distance and require the photographer to transfer the value to the lens focus ring; cameras without built-in rangefinders could have an external rangefinder fitted into the accessory shoe. Earlier cameras of this type had separate viewfinder and rangefinder windows; later the rangefinder was incorporated into the viewfinder. More modern designs have rangefinders coupled to the focusing mechanism so that the lens is focused correctly when the rangefinder images fuse; compare with the focusing screen in non-autofocus SLRs.
A pinhole camera is a simple camera without a lens but with a tiny aperture —effectively a light-proof box with a small hole in one side. Light from a scene passes through the aperture and projects an inverted image on the opposite side of the box, which is known as the camera obscura effect. The size of the images depends on the distance between the object and the pinhole.
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power.
A twin-lens reflex camera (TLR) is a type of camera with two objective lenses of the same focal length. One of the lenses is the photographic objective or "taking lens", while the other is used for the viewfinder system, which is usually viewed from above at waist level.
A camera lens is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.
In photography and cinematography, a wide-angle lens refers to a lens whose focal length is substantially smaller than the focal length of a normal lens for a given film plane. This type of lens allows more of the scene to be included in the photograph, which is useful in architectural, interior, and landscape photography where the photographer may not be able to move farther from the scene to photograph it.
Stereoscopy is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. The word stereoscopy derives from Greek στερεός (stereos) 'firm, solid', and σκοπέω (skopeō) 'to look, to see'. Any stereoscopic image is called a stereogram. Originally, stereogram referred to a pair of stereo images which could be viewed using a stereoscope.
In photography and cinematography, perspective distortion is a warping or transformation of an object and its surrounding area that differs significantly from what the object would look like with a normal focal length, due to the relative scale of nearby and distant features. Perspective distortion is determined by the relative distances at which the image is captured and viewed, and is due to the angle of view of the image being either wider or narrower than the angle of view at which the image is viewed, hence the apparent relative distances differing from what is expected. Related to this concept is axial magnification -- the perceived depth of objects at a given magnification.
The Canon EF-S lens mount is a derivative of the EF lens mount created for a subset of Canon digital single-lens reflex cameras with APS-C sized image sensors. It was released in 2003. Cameras with the EF-S mount are backward compatible with the EF lenses and, as such, have a flange focal distance of 44.0 mm. Such cameras, however, have more clearance, allowing lens elements to be closer to the sensor than in the EF mount. Only Canon cameras released after 2003 with APS-C sized sensors support the EF-S mount.
In photography, a viewfinder is what the photographer looks through to compose, and, in many cases, to focus the picture. Most viewfinders are separate, and suffer parallax, while the single-lens reflex camera lets the viewfinder use the main optical system. Viewfinders are used in many cameras of different types: still and movie, film, analog and digital. A zoom camera usually zooms its finder in sync with its lens, one exception being rangefinder cameras.
A digital single-lens reflex camera is a digital camera that combines the optics and the mechanisms of a single-lens reflex camera with a solid-state image sensor and digitally records the images from the sensor.
In photography, a shutter is a device that allows light to pass for a determined period, exposing photographic film or a photosensitive digital sensor to light in order to capture a permanent image of a scene. A shutter can also be used to allow pulses of light to pass outwards, as seen in a movie projector or a signal lamp. A shutter of variable speed is used to control exposure time of the film. The shutter is constructed so that it automatically closes after a certain required time interval. The speed of the shutter is controlled by a ring outside the camera, on which various timings are marked.
Deep focus is a photographic and cinematographic technique using a large depth of field. Depth of field is the front-to-back range of focus in an image, or how much of it appears sharp and clear. In deep focus, the foreground, middle ground, and background are all in focus.
The over-the-shoulder shot is a camera angle used in film and television, where the camera is placed above the back of the shoulder and head of a subject. This shot is most commonly used to present conversational back and forth between two subjects. With the camera placed behind one character, the shot then frames the sequence from the perspective of that character. The over-the-shoulder shot is then utilised in a shot-reverse-shot sequence where both subject's OTS perspectives are edited consecutively to create a back and forth interplay, capturing dialogue and reactions. This inclusion of the back of the shoulder allows audiences to understand the spatial relationships between two subjects, while still being able to capture a closer shot of each subject’s facial expression. In film and television, the filmmaker or cinematographer’s choice of an OTS shot’s camera height, the use of focus and lenses affect the way audiences interpret subjects and their relationships to others and space.
VR photography is the interactive viewing of panoramic photographs, generally encompassing a 360-degree circle or a spherical view. The results is known as VR photograph, 360-degree photo, photo sphere, or spherical photo, as well as interactive panorama or immersive panorama.
Digital 3D is a non-specific 3D standard in which films, television shows, and video games are presented and shot in digital 3D technology or later processed in digital post-production to add a 3D effect.
The Fujifilm FinePix Real 3D W series is a line of consumer-grade digital cameras designed to capture stereoscopic images that recreate the perception of 3D depth, having both still and video formats while retaining standard 2D still image and video modes. The cameras feature a pair of lenses, and an autostereoscopic display which directs pixels of the two offset images to the user's left and right eyes simultaneously. Methods are included for extending or contracting the stereoscopic baseline, albeit with an asynchronous timer or manually depressing the shutter twice. The dual-lens architecture also enables novel modes such as simultaneous near and far zoom capture of a 2D image. The remainder of the camera is similar to other compact digital cameras.
2D to 3D video conversion is the process of transforming 2D ("flat") film to 3D form, which in almost all cases is stereo, so it is the process of creating imagery for each eye from one 2D image.
Stereo photography techniques are methods to produce stereoscopic images, videos and films. This is done with a variety of equipment including special built stereo cameras, single cameras with or without special attachments, and paired cameras. This involves traditional film cameras as well as, tape and modern digital cameras. A number of specialized techniques are employed to produce different kinds of stereo images.