|
Build Tilt-Shift Camera and Lens Tilt-Shift Photography 
Tilt-shift photography is an artistic technique where the lens is tilted and shifted relative to the attached camera.
InventionThe technique has been around since the very early days of the large format camera where the front glass element could be moved independently of the other to create a sweet spot of focus. The technology has since then been made available for 35 mm cameras where a lens has an element in the front that moves independently of the other. The lens is frequently used in architectural photography to correct distortion, which rather than create sweet spots of focus keeps an entire frame in focus but minimizes the effects of convergence. Other photographers have popularized the lens by using it in portrait photography, a technique which has been compelling as the sweet spot of focus draws the viewer in immediately. Walter Iooss Jr. of Sports Illustrated, Vincent Laforet and many other photographers have images using this lens/technique on their respective websites. Application of techniqueOn a view camera, the lens and camera are connected by a bellows. When tilt is applied, the film or image sensor is not at a right angle to the optical axis of the lens, causing a gradient of focus. The technique can also be done with a modern camera by constructing a tilted lens manually. Uses of effectBy blurring, the viewer's gaze may be directed away from parts of the image the photographer wishes to de-emphasize. A smaller depth of field can also be simulated by bringing the foreground and/or background out of focus. Perspective can be corrected for by sharpening the focus of a foreground and background that would otherwise be outside the depth of field; in theory, perfect perspective correction happens when the planes of the lens, the image sensor, and the object being imaged all intersect. [1] Miniature fakingMiniature faking, in which the location in the photograph appears to have been created in miniature, can be done using the technique.[1]
Tilt-shift miniature faking is a process in which a photograph of a life-size location or object is manipulated so that it looks like a photograph of a miniature scale model. By distorting the focus of the photo, the artist simulates the shallow depth of field normally encountered with macro lenses making the scene seem much smaller than it actually is. Many miniature faked photographs are taken from a high angle to further simulate the effect of looking down on a miniature. Objects oriented horizontally, such as the train in the first example, make better subjects for tilt-shift miniature faking than vertically oriented objects such as in the second example, in which one can see how the bottom of the trees are in focus but the top of the trees are out of focus, despite being the same distance from the lens. TechniquesThe effect can be achieved optically by using a tilt-shift lens. It can also be achieved using an image editor by blurring the top and bottom of the photograph so that only the subject is in focus. The freedom of having an editable gradient map in the digital world allows for a greater degree of control over which areas in the foreground and background are going to be blurred. Other techniques to enhance the effect involve increasing the contrast of the picture, simulating the darker, harder shadows of a miniature under a light and increasing the saturation of the picture, because fake houses and people are often painted with brighter, more basic paints. It is perhaps improper to refer to this technique as "tilt-shifting". These more detailed digital "fakes" do not simulate the effect of tilt-shifting per se, rather it merely simulates the effect of photographing a miniature, and to a much more realistic effect than a tilt-shifted photograph. Usage
See alsoExternal links
References
In photography, a perspective correction lens (also known as a PC lens, perspective control lens, or shift lens, or — if the lens can also tilt — a tilt and shift or TS lens) allows the photographer to correct for the effects of perspective by shifting the lens in relationship to the film or sensor area. This type of lens is mostly used in architectural and other technical photography. Perspective control lenses are generally made for single-lens reflex (SLR) 35mm and medium-format SLR cameras, as most large format cameras allow for perspective correction using movements. A perspective control lens has a larger image circle than is required to cover the image area (film or sensor size). Typically, the image circle is large enough, and the mechanics of the lens sufficiently limited, that the film plane cannot be shifted outside of the image area. However, all PC lenses require a small aperture setting to prevent vignetting when significant shifts are employed. PC lenses for 35mm cameras typically offer a maximum shift of 11mm. The first PC lens manufactured for a SLR camera in any format was Nikon's 1961 f/3.5 PC-Nikkor. It was followed by an f/2.8 35mm PC-Nikkor and an f/3.5 28mm PC-Nikkor. Other manufacturers, including Olympus, Pentax, Schneider Kreuznach (produced as well for Leica), and Minolta, made their own versions of PC lenses. Olympus produced a 35mm shift lens and a 24mm shift lens. Applications
When making photographs of buildings or other large structures from the ground, it is often impossible (without shift) to fit the entire building in the frame without tilting the camera upwards. The resultant perspective causes the top of the building to appear smaller than its base, which is often considered undesirable (a). The perspective effect is proportional to the lens's angle of view. Photographing from the ground, perspective can be eliminated by keeping the film plane parallel to the building. With ordinary lenses, this results in capturing only the bottom part of the subject (b). With a perspective control lens, however, the lens may be shifted upwards in relation to the film plane, placing more of the subject within the frame (c). The ground level, the camera's point of perspective, is shifted towards the bottom of the frame. Another use of shifting is in taking pictures of a mirror. By moving the camera off to one side of the mirror, and shifting the lens in the opposite direction, an image of the mirror can be captured without the reflection of the camera or photographer. Shifting can similarly be used to photograph 'around' objects, such as a building support in a gallery, without producing an obviously oblique view. Available lensesIn the 35mm film format, PC lenses for architectural photography have appeared in focal lengths of 24mm, 28mm, 35mm, 45mm, 85mm and 90 mm. The earliest such lenses were those of 35mm, which is now considered too long for many applications. With advances in optical design, lenses of 28mm and then 24mm became available and were quickly adopted by photographers working in close proximity to their subjects, such as in urban settings. A unique 85mm PC lens produced by Nikon offers both tilt and shift movements, and close focus for macrophotography. PC lenses are all prime lenses. They can be quite expensive compared to regular prime lenses. Some medium format camera makers, such as Mamiya, have addressed this problem by offering shift adapters that work with the maker's other prime lenses. Perspective correction in softwareComputer software (such as Photoshop's perspective and distort functions) can be used to correct perspective effects in post-production, but cannot recover lost optical resolution in the more distant portions of the subject. Gallery of perspective correction lenses
ReferencesExternal links
This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia Encyclopedia article "Tilt-Shift Photography" |
