View camera
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The view camera is a type of camera first developed in the era of the Daguerreotype[1] and still in use today, though with many refinements. It comprises a flexible bellows which forms a light-tight seal between two adjustable standards one of which holds a lens, and the other a viewfinder or a photographic film holder.[2]
The bellows is a flexible, accordion-pleated box, which encloses the space between the lens and film, and has the ability to flex to accommodate the movements of the standards.[3]
The front standard is a board at the front of the camera which holds the lens and, usually, a shutter.
At the other end of the bellows, the rear standard is a frame which holds a ground glass, used for focusing and composing the image before exposure, which is replaced by a holder containing the light-sensitive film, plate, or image sensor for exposure. The front and rear standards can move in various ways relative to each other, unlike most other types of camera, giving control over focus, depth of field and perspective.
The camera must have some means of support, usually provision for mounting it on a tripod.
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[edit] Types of view camera
View cameras use large format sheet film, using one sheet per photograph. Standard sizes in inches are: 4×5, 5×7, 4×10, 5×12, 8×10, 11×14, 7×17, 8×20, 12×20, 20×24, and 30×40. (It is usual to list the short side first in the Americas, and the long side in many other countries, thus 4×5 is the same as 5×4).) A similar, but not identical, range of metric sizes is used in many countries; thus 9×12 cm is similar to, but not interchangeable with, 4×5 inches. The most widely used format is 4×5, followed by 8×10.
A few rollfilm cameras have movements that make them as versatile as a sheet film view camera. Rollfilm and instant film backs are available to use in place of a sheetfilm holder on a single-film camera.
There are several types of view camera for different purposes and allowing different degrees of movement and portability. They include:
- Monorail camera - This is the most common type of studio view camera, with the front and rear standards being mounted to a single rail that is fixed to a camera support. This design allows the greatest range of movements and flexibility, with both front and rear standards able to tilt, shift, rise, fall and swing in similar proportion. These are generally made of metal with leather or synthetic bellows, and are difficult to pack for travel. Sinar and Toyo are popular manufacturers of monorail view camera systems. ARCA-Swiss produces monorail cameras for field use in addition to models for the more conventional studio applications. Many manufacturers also offer monorail extensions, which permit the front or rear standards to move further away from each other, allowing for focus on very close objects (macrophotography). Bender Photographic produce relatively inexpensive kits to build a wooden 4×5 or 8×10 inch monorail camera.
- Field camera - These have the front and rear standard mounted on sliding rails fixed to a hinged flat bed that is fixed to a camera support (tripod, etc.). These cameras are usually made of wood, or sometimes lightweight and strong composites such as carbon fiber. When the bellows is fully retracted the flat bed can be folded up, reducing the camera to a relatively small, light, and portable box. The price for this portability is that the standards are not as mobile or as adjustable as those of a monorail design; the rear standard, in particular, may be fixed and offer no movement. These large format but transportable cameras are popular with landscape photographers. Tachihara and Wisner are examples of modern field cameras at opposite ends of the price scale.
- Extremely large field cameras using 11×14 film and larger, or panoramic film sizes such as 4×10 or 8×20, are sometimes referred to as banquet cameras, and were used to photograph large, posed groups of people to mark an occasion, such as a banquet or a wedding.
- Studio and salon cameras are similar to field cameras, but do not fold up for portability.
- Press and technical cameras also use sheet film but are not true view cameras.
[edit] Movements
Photographers use view cameras to control focus and convergence of parallel lines. Image control is done by moving the front and/or rear standards. Movements are the ways the front and rear standards can be positioned to alter perspective and focus. The term can also refer to the mechanisms on the standards that allow the position to be achieved.
Not all cameras have all movements available to both the front and rear standards, and some cameras have more movements available than others. Some cameras have mechanisms that make intricate movement combinations easier for the photographer.
Some limited view camera-type movements are possible with SLR cameras using various perspective control lenses. Also, as use of view cameras declines in favor of digital photography, these movements are being simulated using computer software.
[edit] Rise and fall
Rise and fall are the movements of either the front or rear standard vertically along a line in a plane parallel to the film plane. Rise is a very important movement especially in architectural photography. Generally, the lens is moved vertically—either up or down—along the lens plane in order to change the portion of the image that will be captured on the film.
In the 35mm format, special shift lenses emulate the rise or fall of view cameras.
The main effect of rise is to eliminate converging parallels when photographing tall buildings. If a camera without movements is pointed at a tall building, the top will be cut off; if the camera is tilted upwards to get it all in, the film plane will not be parallel to the building, and the building will seem narrower at the top than the bottom; lines which are parallel in the object will converge in the image.
To avoid this apparent distortion, a wide-angle lens will get more of the building in, but will include more of the foreground and alter the perspective.
A camera with rising front allows a normal lens to be raised to include the top of the building without tilting the camera.
This requires the image circle of the lens to be larger than is required to cover the film without use of movements. If the lens can produce a circular image just large enough to cover the film, it will no longer cover the bottom of the film as it rises. Consequently the lens coverage must be larger if rises (and falls, and shifts) are to be used.
In Figure a) below (images are upside down, as a photographer would see them on the ground glass of a view camera), the lens is in the “normal” position. Notice that much of the unwanted foreground is included, but not the top of the tower. In Figure b), the lens has been shifted up: the top of the tower is now inside the area captured on film, at the sacrifice of unwanted green foreground.
[edit] Shift
Moving the front standard left or right from its normal position is called lens shift or simply shift. This movement is similar to rise and fall, but moves the image horizontally rather than vertically. One use for shift is to remove the image of the camera from the final image when photographing a reflective surface.
[edit] Tilt
The axis of the lens is normally perpendicular to the film. Changing the angle between axis and film by tilting the lens standard backwards or forwards is called lens tilt or just tilt. Tilt is especially useful in landscape photography. By using the Scheimpflug principle, the “plane of sharp focus” can be changed so that any plane can be brought into sharp focus. When the film plane and lens plane are parallel as is the case for most 35mm cameras, the plane of sharp focus will also be parallel to these two planes. If, however, the lens plane is tilted with respect to the film plane, the plane of sharp focus will also be tilted according to geometrical and optical properties. The three planes will intersect in a line below the camera for downward lens tilt. The tilted plane of sharp focus is very useful in that this plane can be made to coincide with a near and far object. Thus, both near and far objects on the plane will be in focus.
This effect is often incorrectly thought of as increasing the depth of field. Depth of field depends on the focal length, aperture, and subject distance. As long as the photographer wants sharpness in a plane that is parallel to the film, tilt is of no use. However, tilt has a strong effect on the depth of field by drastically altering its shape, making it asymmetrical. Without tilt, the limits of near and far acceptable focus are parallel to the plane of sharp focus as well as parallel to the film. With forward tilt, the plane of sharp focus tilts even more and the near and far limits of acceptable focus form a wedge shape (viewed from the side). Thus, the lens still sees a cone shaped portion of whatever is in front of it while the wedge of acceptable focus is now more closely aligned with this cone. Therefore, depending on the shape of the subject, a wider aperture can be used, lessening concerns about camera stability due to slow shutter speed and diffraction due to too-small aperture.
The purpose of tilting is to achieve the desired depth of field using the aperture at which the lens used performs best. Using too small an aperture risks losing to diffraction and camera or subject motion what one gains from depth of field. Only testing a given scene, or experience, will show whether tilting is better than leaving the standards neutral and relying on the aperture alone to achieve the desired depth of field. If the scene is sharp enough at f/32 with 2 degrees of tilt but would need f/64 with zero tilt, then tilt is the solution. If another scene would need f/45 with or without tilt, then nothing is gained.
With a forward tilt, the shape of the portion of a scene in acceptable focus is a wedge. Thus, the scene most likely to benefit from tilting is short in the front and expands to a greater height or thickness toward the horizon. A scene consisting of tall trees in the near, middle and far distance may not lend itself to tilting unless the photographer is willing to sacrifice either the top of the near trees and/or the bottom of the far trees.
Assuming lens axis front tilt, here are the trade offs in choosing between a small degree of tilt (say less than 3) and a larger tilt: A small tilt causes a wider or fatter wedge but one that is far off axis from the cone of light seen by the lens. Conversely, a large tilt (say 10 degrees) causes the wedge to be more aligned with the view of the lens but with a narrower wedge. Thus, a modest tilt is often, or even usually, the best starting point. See Focusing the View Camera by Harold Merklinger.
Small and medium format cameras have fixed bodies that do not allow for misalignment of the film and lens planes, intentionally or not. Tilt and shift lenses that allow these cameras to have a small amount of adjustment, mostly rise and fall, can be purchased from a number of lens makers. High quality tilt/shift lenses are quite expensive. The price of a new Nikon tilt/shift lens is comparable to that of a good used large-format camera which offers a much greater range of adjustment.
[edit] Swing
Altering the angle of the lens standard in relation to the film plane by swiveling it from side to side is called swing. Swing is similar to tilt, but in the horizontal axis. Swing may be used to achieve sharp focus along the entire length of a picket fence, for example.
[edit] Back Tilt/Swing
Angular movements of the rear standard change the angle between the lens plane and the film plane just as front standard angular movements do. Although rear standard tilt will change the plane of sharp focus in the same manner as front standard tilt does, this is not usually the reason rear tilt/swing is used. When a lens is a certain distance (its focal length) away from the film, distant objects such as faraway mountains are in focus. Moving the lens farther from the film brings closer objects into focus. Tilting or swinging the film plane puts one side of the film farther from the lens than the center is and the opposite point of the film is therefore closer to the lens.
One reason to swing or tilt the rear standard is to keep the film plane parallel to the face of the object being photographed. Another reason to swing or tilt the rear standard is to control apparent convergence of lines when subjects are shot at an angle.
It is often incorrectly stated that rear movements can be used to change perspective. The only thing that truly controls perspective is the location of the camera in relation to the objects in the frame. Rear movements can allow a photographer to shoot a subject from a perspective that places him or her at an angle to the subject, yet still achieve parallel lines. Thus, rear movements allow a change of perspective by allowing a different camera location, yet no view camera movement will actually alter perspective.
[edit] Lenses
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A view camera lens typically consists of:
- A front lens element, sometimes referred to as a cell.
- A shutter, which consists of an electronic or spring-actuated iris which controls exposure duration. Some early shutters were actuated by air. For long exposures, a lens with no shutter (a barrel lens) can be uncovered for the duration of the exposure by removing a lens cap.
- The aperture diaphragm
- A lensboard: a flat board, typically square in shape and made of metal or wood, designed to lock securely into the front standard of a particular view camera, with a central hole of the right size to insert a lens and shutter assembly, usually secured and made light-tight by screwing a ring onto a thread on the rear of the lens assembly. Lensboards complete with lenses can be removed and fitted very quickly.
- A rear lens element (or cell).
Almost any lens of the appropriate coverage area may be used with almost any view camera. All that is required is that the lens be mounted on a lensboard compatible with the camera. Not all lensboards work with all models of view camera, though different cameras may be designed to work with a common lensboard type. Lensboards usually come with a hole sized according to the shutter size, often called the Copal Number. Copal is the most popular maker of leaf shutters for view camera lenses. The following is a list of the Copal Number and the corresponding hole diameter required in the lensboard to mount the shutter:
- Copal #0 - 34.6 mm
- Copal #1 - 41.6 mm
- Copal #3 - 65 mm
- Copal #3s - 64.5 mm
The lens is designed to split into two pieces, the front and rear elements screwed, usually by a trained technician, into the front and back of the shutter assembly, and the whole fitted in a lensboard.
View camera lenses are designed with both focal length and coverage in mind - a 300mm lens may give a different angle of view (either over 31° or over 57°) depending on whether it was designed to cover a 4×5 or 8×10 image area. Most lenses are designed to cover more than just the image area to allow camera movements.
Focusing involves moving the entire front standard with the lens assembly closer to or further away from the rear standard, unlike many lenses on smaller cameras in which one group of lens elements is fixed and another moves.
Very long-focus lenses may require the camera to be fitted with special extra-long rails and bellows. Very short focal length wide-angle lenses may require the standards to be closer together than a normal concertina-folded bellows will allow; a bag bellows, a simple light-tight flexible bag must be used. Recessed lensboards are also sometimes used to get the rear element of a wide angle lens close enough to the film plane; they may also be of use when true telephoto, as distinct from long-focus, lenses are used.
Zoom lenses are not used in view camera photography, as there is no need for rapid and continuous change of focal length with static subjects, and the price, size, weight, and complexity would be excessive. Some lenses are "convertible": the front or rear element only, or both elements, may be used, giving three different focal lengths, although the quality of the single elements will not be as good at larger apertures as the combination. These are popular with field photographers who can save weight by carrying one convertible lens rather than two or three lenses of different focal lengths. Older convertible lenses may not be corrected for chromatic aberration, making them useless with color film.
Soft focus lenses introduce spherical aberration deliberately into the optical formula for an ethereal effect considered pleasing, and flattering to subjects with less than perfect complexions. The segree of soft-focus effect is determined by either aperture size or special disks that fit into the lens to modify the aperture shape. Some antique lenses, and some modern SLR soft focus lenses, have a lever which controls the softening effect by altering the optical formula.
Current large format lens manufacturers:
- Schneider Kreuznach - Price-no-object high quality lenses.
- Nikon - Noted for its high quality telephoto designs. As of January 2006, Nikon announced it would discontinue manufacturing its LF lenses.
- Rodenstock - Extremely high quality, reasonably priced.
- Fujinon - Has a strong presence in Asia.
- Cooke - Interesting and expensive soft focus and color-corrected convertible lenses.
- Congo - Budget lenses, but offering interesting soft focus and telephoto designs.
- Seagull/Shen-Hao/Sinotar - Budget lenses.
- Wisner - Offer a modern convertible Plasmat set.
- Sinar - Rebranded Rodenstock lenses.
- Caltar - Rebranded Rodenstock lenses.
- Linhof - Rebranded Rodenstock and Schneider lenses.
[edit] Film
View cameras use sheet film but can use roll film (generally 120/220 size) by using special roll film holders. Popular "normal" image formats for the 4×5 camera are 6×6, 6×7, and 6×9cm. 6×12 and 6×17cm are suited to panoramic photography.
With an inexpensive modification of the darkslide requiring no modification to the camera, half a sheet of film can be exposed at a time. While this technique could be used for economy where a larger image is not required, it is almost always used with the intention of obtaining a panoramic format so that, for example, a 4×5 camera can take two 2×5 photos, an 8×10 can take two 4×10s etc. This is popular for landscape photography, and in the past was common for group photographs.
Digital backs are available for view cameras to create digital images instead of using film. Prices are high compared to smaller digital cameras.
[edit] Operation
The camera must be set up in a suitable position. In some cases the subject can also be manipulated, as in a studio; in others the camera must be positioned to photograph a subject such as a landscape. The camera must be mounted in a way that prevents camera motion for the duration of the exposure. Usually a tripod is used; two may be required for a long camera.
To operate the view camera, the photographer opens the shutter on the lens to focus and compose the image on a ground glass plate on the rear standard. The ground glass is held in the same plane that the film will later occupy, so that an image that is well focused on the ground glass will be well focused on the film. The ground glass image is somewhat dim and can be difficult to view in bright light. The photographer will often use a focusing cloth or "dark cloth" over his or her head, and the rear of the camera. The dark cloth shrouds the viewing area and keeps environmental light from obscuring the image. In the dark space created by the dark cloth, the image appears as bright as it can and allows the image to be most easily viewed, assisting in focusing and composition.
Often a photographer will use a magnifying lens, usually a high quality loupe, to critically focus the image. An addition over the ground glass called a Fresnel lens can considerably brighten the ground glass image (albeit with a slight loss of focusing accuracy). The taking lens may be stopped down to help gauge depth of field effects and vignetting, but while the image is being composed the lens is generally opened to its widest setting to aid in focusing.
The ground glass and frame assembly, known as the spring back, is held in place by springs that pull and hold the ground glass firmly into the plane of focus during the focusing and composition process. Once the focusing process is complete, the same springs act as a flexible clamping mechanism to press the film holder into the same plane of focus the ground glass occupied. To take the photograph the ground glass is pulled back and the film holder is slid into its place.
The shutter is then closed and cocked, the shutter speed and aperture set, and the darkslide of the film holder removed, revealing the sheet of film. The shutter is then triggered, the exposure made, and the darkslide replaced into the film holder.
Sheet film holders are generally interchangeable between the various brands and models of view camera, in the most common formats, adhering to a set of standards. The largest cameras and more uncommon formats are less standardized.
There are special film holders and accessories that fit in place of a standard film holder, such as Grafmatic, which could fit six sheets of film in the space of an ordinary two-sheet holder, and some light meters have an attachment that inserts into the film holder slot on the camera back that allows the photographer to measure light falling at a specific point on the film plane. The entire film holder/back assembly is often an industry standard Graflex back, removable so accessories like roll-film holders and digital imagers can be used without altering focus.
[edit] Pros and cons compared to medium & 35mm formats
[edit] Advantages
- The ability to skew the plane of critical focus. In a camera without movements the film plane is always parallel to the lens plane. A camera with tilts and swings allows the plane of focus to be skewed away from the parallel in any direction, which in many cases can bring the image of a subject which is not parallel to the lens plane into near-to-far focus without the need to stop down excessively. Both standards can be tilted through the horizontal or swung through the vertical axes to change the plane of focus. Tilts and swings of the front standard alone do not alter or distort shapes or converging lines in the image; tilts and swings of the rear standard do affect these things, as well as the plane of focus: if the plane of focus must be skewed without altering shapes in the image, front movements alone must be used. The Scheimpflug principle explains the relationship between lens tilts and swings, and the plane of sharp focus.
- The ability to distort the shape of the image by skewing the film plane, most often to reduce or eliminate, or deliberately exaggerate, convergence of lines which are parallel in the subject. If a camera with parallel film and lens planes is pointed at an angle to a plane subject with parallel lines, the lines will appear to converge in the image, becoming closer to each other the further away from the camera they are. With a view camera the rear standard can be swung toward the wall to reduce the convergence. If the standard is parallel to the wall convergence is entirely eliminated. Moving the rear standard in this way skews the plane of focus; this can be corrected with a front swing in the same direction as the rear swing.
- Improved image quality for a print of a given size. The larger a piece of film is, the less detail is lost at a given print size because the larger film requires less enlargement for the same size print. In other words, the same scene photographed on a large-format camera will give a better-quality image and allow greater enlargement than if photographed on a smaller format. Additionally, the larger a piece of film is, the more subtle and varied the tonal pallette and gradations are at a given print size. A large film size also allows same-size contact printing.
- Smaller apertures can be used: much smaller apertures can be used than with smaller format cameras before diffraction becomes significant for a given print size.
- The camera operator is forced to think more than is required with a hand-held camera with exposure metering and automatic focussing, as the camera is cumbersome and slow to set up, and without automatic features. An ambiguous advantage.
- Low resale value is an advantage for buyers, but not for sellers. A top-of-the-line 8×10 camera that cost $8,000 new can often be bought in excellent condition, with additional accessories, for $1,500.
[edit] Disadvantages
- Lack of automation: most view cameras are fully manual, requiring time, and allowing even experienced photographers to make mistakes. Some cameras, such as Sinars, have some degree of automation with self-cocking shutters and film-plane metering.
- Large size and weight: the old adage "View camera photographers have strong backs and weak minds" may raise a smile from some practitioners. This and the previous point make view cameras unsuitable for action photography.
- Shallow depth of field: view cameras require longer focal length lenses than smaller format cameras, especially for the larger sizes, with shallower depth of field. This can be turned to advantage; some photographers make use of the narrow range of sharp focus and blurred rendering of background and even foreground.
- Small maximum aperture: it is not feasible to make long focal length lenses with the wide maximum apertures available with shorter focal lengths.
- High cost: there is limited demand for view cameras, so that there are no economies of scale and they are much more expensive than mass-produced cameras. Some are hand-made. The cost of sheet film and processing is much higher than rollfilm.
- Poor availability: many large-format products have been discontinued, and others are increasingly expensive as demand declines. It becomes difficult and expensive, or impossible, to obtain required equipment and materials.
Some of these disadvantages can be turned into advantages. For example, slow setup and composure time allow the photographer to better visualize the image before making an exposure. The shallow depth of field can be used to emphasize certain details and deemphasize others, especially combined with camera movements. The high cost of film and processing encourages experimentation. Because view cameras are rather difficult to set up and focus, the photographer must seek the best camera position, perspective, etc. before exposing. Beginning 35mm photographers are even sometimes advised to use a tripod specifically because it will slow down the picture-taking process.
[edit] See also
[edit] References
- ^ Stroebel, L. D. (1986). View Camera Technique, 5th ed., p. 212. Boston: Focal Press. ISBN 0-240-51711-3
- ^ Stroebel (1986). p. 2.
- ^ Adams, A. (1980). The Camera, p. 34. Boston: Little, Brown and Company. ISBN 0-8212-1092-0
