Photography: Laws, U.S.A.

In general photography for personal reasons will cause little legal conflict, however with issues of privacy and copyright, as well as potentially espionage, terrorism and harassment, laws where they exist, can be complicated.

United States of America

Local, state, and national laws may exist pertaining to photographing or videotaping. Laws that are present may vary from one jurisdiction to the next, and may be stricter in some places and more lenient in others, so it is important to know the laws present in one’s location. Typical laws in the United States are as follows:
It is generally legal to photograph or videotape anything and anyone on any public property, with some exceptions.

Filming of private property from within the public domain is legal, with the exception of an area that is generally regarded as private, such as a bedroom, bathroom, or hotel room. (For example, you may take a picture of the exterior of a house from the street, but not the bedroom with the open curtain).
Many places now have laws prohibiting filming private areas under a person’s clothing without that person’s permission. This also applies to any filming of another within a public restroom or locker room. Some jurisdictions have completely banned the use of a camera phone within a restroom or locker room in order to prevent this. It is expected that all 50 states will eventually have laws pertaining to surreptitiously filming a person’s genitalia.

Taking a photograph while on an airplane is banned in many places, and many mass transit systems prohibit taking photographs or videos while on board buses or trains or inside of stations. Photography and videography are also prohibited in the U.S. Capitol, in courthouses, and in government buildings housing classified information. Bringing a camera phone into one of these buildings is not permitted either.

* Filming while on private property follows many restrictions. The owner of the property is permitted to film their own property. However, they must receive permission from others on the property to be allowed to film that person.

* In order to film someone else’s property, permission must be received from the owner.

* Photographing or videotaping a tourist attraction, whether publicly or privately owned, is generally considered legal, unless explicitly prohibited by posted signs.

* Photographing of privately-owned property that is generally open to the public (i.e. retail) is permitted unless explicitly prohibited by posted signs.

* Some jurisdictions have laws regarding filming while in a hospital or health care facility. Where permitted, such filming may be useful in gathering evidence in cases of abuse, neglect, or malpractice.
* One must not hinder the operations of law enforcement, medical, emergency, or security personnel by filming.
* Any filming with the intent of doing unlawful harm against a subject may be a violation of the law in itself.

Photography: Laws, U.K.

In general photography for personal reasons will cause little legal conflict, however with issues of privacy and copyright, as well as potentially espionage, terrorism and harassment, laws where they exist, can be complicated.

United Kingdom
In general under the law of the United Kingdom one cannot prevent photography of private property from a public place, and in general the right to take photographs on private land upon which permission has been obtained is similarly unrestricted. However a landowner is permitted to impose any conditions they wish upon entry to a property, such as forbidding or restricting photography. Two public locations in the UK, Trafalgar Square and Parliament Square have a specific provision against photography for commercial purposes, as do Royal Parks (as private land).

Photography of individuals is unrestricted where the subject has a reasonable expectation of being photographed, such as on the street or at a tourist attraction. Photography without consent of someone in a place where they have a reasonable expectation of privacy, could be considered to be against the European convention on human rights, however in general there is no right to privacy under UK law, and photograph of individuals may be used for any purposes. In addition persistent or aggressive photography of a single individual may come under the legal definition of harassment.

In general, schools disallow photography and video recording of people due to privacy concerns

Photography: Vignetting, Post Shoot

For artistic effect, vignetting is sometimes applied to an otherwise un-vignetted photograph and can be achieved by burning the outer edges of the photograph (with film stock) or using digital imaging techniques, such as masking darkened edges.In digital imaging, this technique is used to create a more film-like appearance in the picture.

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Photography: Vignetting, Causes

Mechanical vignetting

Mechanical vignetting occurs when light beams emanating from object points located off-axis are partially blocked by external objects such as thick or stacked filters, secondary lenses, and improper lens hoods. The corner darkening can be gradual or abrupt, depending on the lens aperture. Complete blackening is possible with mechanical vignetting.

Optical vignetting

This type of vignetting is caused by the physical dimensions of a multiple element lens. Rear elements are shaded by elements in front of them, which reduces the effective lens opening for off-axis incident light. The result is a gradual decrease of the light intensity towards the image periphery. Optical vignetting is sensitive to the aperture and can be completely cured by stopping down the lens. Two or three stops are usually sufficient.

Natural vignetting

Unlike the previous types, natural vignetting (also known as natural illumination falloff) is not due to the blocking of light rays. The falloff is approximated by the cos4 or “cosine fourth” law of illumination falloff. Here, the light falloff is proportional to the fourth power of the cosine of the angle at which the light impinges on the film or sensor array. Wideangle rangefinder designs and the lens designs used in compact cameras are particularly prone to natural vignetting. Telephoto lenses, retrofocus wideangle lenses used on SLR cameras, and telecentric designs in general are less troubled by natural vignetting. A gradual grey filter or postprocessing techniques may be used to compensate for natural vignetting, as it cannot be cured by stopping down the lens.

Pixel vignetting

Pixel vignetting only affects digital cameras and is caused by angle-dependence of the digital sensors. Light incident on the sensor at a right angle produces a stronger signal than light hitting it at an oblique angle. Most digital cameras use built-in image processing to compensate for optical vignetting and pixel vignetting when converting raw sensor data to standard image formats such as JPEG or TIFF. The use of microlenses over the image sensor can also reduce the effect of pixel vignetting.

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Photography: Vignetting

VIGNETTING AND LOMOGRAPHY LOOKS THE SAME — ALMOST! BUT STILL DIFFERENT

photography and optics, vignetting is a reduction of an image’s brightness or saturation at the periphery compared to the image center.
Although vignetting is normally unintended and undesired, it is sometimes purposely introduced for creative effect, such as to draw attention to the center of the frame. A photographer may deliberately choose a lens which is known to produce vignetting. It can also be produced with the use of special filters or post-processing procedures. Vignetting is commonly found on video games from the seventh generation.

Causes

There are several causes of vignetting. Sid Ray distinguishes the following types:

Mechanical vignetting
Optical vignetting
Natural vignetting
A fourth cause is unique to digital imaging:
Pixel vignetting

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Photography: Lomography

Lomography is the commercial trademark of Lomographische AG, Austria for products and services related to photography. The name is inspired by the former state-run optics manufacturer LOMO PLC of Saint Petersburg, Russia. LOMO PLC created and produced the 35 mm LOMO LC-A Compact Automat camera – which became the centerpiece of Lomography’s marketing and sales activities. This camera was loosely based upon the Cosina CX-1 and introduced in the early 1980s.

In 1991, the Austrian founders of Lomography discovered the Lomo LC-A. As the company states, they were “charmed by the unique, colorful, and sometimes blurry” images that the camera produced. (Of course many cameras can make similar images)After a series of international art exhibitions and aggressive marketing work, Lomography signed an exclusive distribution agreement with LOMO PLC – thereby becoming the sole distributor of all Lomo LC-A cameras outside of the Soviet Union. This monopolistic agreement, their viral/tribal marketing strategies and pricing philosophy have generated controversy. Lomography emphasizes casual, snapshot photography. Characteristics such as over-saturated colors, off-kilter exposure, blurring, “happy accidents,” and alternative film processing are often considered part of the “Lomographic Technique.” Users are encouraged to take a lighthearted approach to their photography, and use these techniques to document everyday life, as the Lomo LC-A’s small size, simple controls, and ability to shoot in low light encourages candid photography, photo reportage, and photo vérité.

Since the introduction of the original Lomo LC-A, Lomography has produced and marketed an entire line of their own branded analog cameras. Most Lomographic cameras are designed to produce a single photographic effect. For example, the Lomography Fisheye camera features a built-in wideangle lens, and shoots fisheye-distorted photos. In 2005, production of the original Lomo LC-A was discontinued. Its replacement, the LC-A+, was introduced in Fall 2006. The new camera, made in China rather than Russia, featured the original Russian lens manufactured by LOMO PLC. This changed as of mid-2007 with the lens now made in China also

Similar to Eastman Kodak’s concept of the “Kodak moment,” the Lomography motto of “don’t think, just shoot” presumes spontaneity, close-ups, and ubiquity, while deemphasizing formal technique (however to take a good ‘from the hip’ shot does take skill). Typical lomography cameras are deliberately low-fidelity and inexpensively constructed. Some cameras make use of multiple lenses and rainbow-colored flashes, or exhibit extreme optical distortions and even light leaks.

Current models marketed by Lomographische AG include Lomo LC-A, Holga, Holga 35mm, Actionsampler, Frogeye, Pop-9, Oktomat, Fisheye, Fisheye2, Colorsplash, Colorsplash Flash, F-stop Bang, SuperSampler, Horizon 202, Seagull TLR, and Smena 8M. The company also resells dead stock Polaroid cameras and Russian dead stock – the sort normally acquired at “quirky, old-school camera shops,” as the company’s web site puts it.

Some photographers feel that the Lomo LC-A lens effect can be digitally emulated with photo-editing software such as GIMP or Photoshop. In addition, the company’s promotional web site for Lomography showcases many high-contrast photographs – with unusual saturation and color – that were created using the technique called cross processing in which film intended for developing in slide chemistry (E-6) is processed in photographic negative chemistry (C-41), and vice versa. This technique can be employed with any film camera and can be somewhat mimicked with digital software as well.

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Photography: Holography, Replication

An existing hologram can be replicated, either in an optical way similar to holographic recording, or in the case of surface relief holograms, by embossing. Surface relief holograms are recorded in photoresists or photothermoplastics, and allow cheap mass reproduction. Such embossed holograms are now widely used, for instance as security features on credit cards or quality merchandise. The Royal Canadian Mint even produces holographic gold and silver coinage through a complex stamping process. The first book to feature a hologram on the front cover was The Skook (Warner Books, 1984) by JP Miller, featuring an illustration by Miller.

The first step in the embossing process is to make a stamper by electrodeposition of nickel on the relief image recorded on the photoresist or photothermoplastic. When the nickel layer is thick enough, it is separated from the master hologram and mounted on a metal backing plate. The material used to make embossed copies consists of a polyester base film, a resin separation layer and a thermoplastic film constituting the holographic layer.

The embossing process can be carried out with a simple heated press. The bottom layer of the duplicating film (the thermoplastic layer) is heated above its softening point and pressed against the stamper so that it takes up its shape. This shape is retained when the film is cooled and removed from the press. In order to permit the viewing of embossed holograms in reflection, an additional reflecting layer of aluminium is usually added on the hologram recording layer.

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Photography: Holography, Recording Media

The recording medium must be able to resolve the interference fringes as discussed above. It must also be sufficiently sensitive to record the fringe pattern in a time period short enough for the system to remain optically stable, i.e any relative movement of the two beams must be significantly less than λ/2.

The recording medium has to convert the interference pattern into an optical element which modifies either the amplitude or the phase of a light beam which is incident upon it. These are known as amplitude and phase holograms respectively. In amplitude holograms the modulation is in the varying absorption of the light by the hologram, as in a developed photographic emulsion which is less or more absorptive depending on the intensity of the light which illuminated it. In phase holograms, the optical distance (i.e. the refractive index or in some cases the thickness) in the material is modulated.

Most materials used for phase holograms reach the theoretical diffraction efficiency for holograms, which is 100% for thick holograms (Bragg diffraction regime) and 33.9% for thin holograms (Raman-Nath diffraction regime, holographic films of typically some μm thickness). Amplitude holograms have a lower efficiency than phase holograms and are therefore used more rarely.

The table below shows the principal materials for holographic recording. Note that these do not include the materials used in the mass replication of an existing hologram. The resolution limit given in the table indicates the maximal number of interference lines per mm of the gratings. The required exposure is for a long exposure. Short exposure times (less than 1/1000th of second, such as with a pulsed laser) require a higher exposure due to reciprocity failure.

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Photography: Holography, Practical Requirements

The object and the reference beams must be able to produce an interference pattern which is stable during the time in which the holographic recording is made. To do this, they must have the same frequency and the same relative phase during this time, that is, they must be mutually coherent. Many laser beams satisfy this condition, and lasers have been used to make holograms since their invention, though it should be noted that the first holograms by Gabor used ‘quasi-chromatic’ light sources. In principle, two separate light sources could be used if the coherence condition could be satisfied, but in practice a single laser is always used.

In addition, the medium used to record the fringe pattern must be able to resolve the fringe patterns and some of the more common media used are listed below. The spacing of the fringes depends on the angle between object and reference beam. For example, if this angle is 45o, and the wavelength of the light is 0.5μm, the fringe spacing is about 0.7μm or 1300 lines/mm. A working hologram can be obtained even if all the fringes are not resolved, but the resolution of the image is reduced as the resolution of the recording medium reduces.

Mechanical stability is also very important when making a hologram. Any relative phase change between the object and reference beams due to vibration or air movement will cause the fringes on the recording medium to move, and if the phase changes is greater than π, the fringe pattern is averaged out, and no holographic recording is obtained. Recording time can be several seconds or more, and given that a phase change of π is equivalent to a movement of λ/2 this is quite a stringent stability equirement.

Generally, the coherence length of the light determines the maximum depth in the scene of interest which can be recorded holographically. A good holography laser will typically have a coherence length of several meters, ample for a deep hologram. Certain pen laser pointers have been used to make small holograms (see External links). The size of these holograms is not restricted by the coherence length of the laser pointers (which can exceed several meters), but by their low power of below 5 mW.

The objects which form the scene must, in general, have optically rough surfaces so that they scatter light over a wide range of angles. A specularly reflecting (or shiny) surface reflects the light in only one direction at each point on its surface, so in general, most of the light will not be incident on the recording medium. It should be noted that the light scattered from objects with a rough surface forms an objective speckle pattern which has random amplitude and phase.

The reference beam is not normally a plane wavefront; it is usually a divergent wavefront which is formed by placing a convex lens in the path of the laser beam.

To re-construct the object exactly from a transmission holgram, the reference beam must have the same wavelength, the same curvature, and must illuminate the hologram at the same angle as the original reference beam. Any slight departure from any of these conditions will give a distorted re-construction, and if the difference between the reconstruction and original reference beam is too great, no re-construction is obtained. Exact re-construction is achieved in holographic interferometry where the holographically re-constructed wavefront interferes with the live wavefront, to map out any displacement of the live object, and gives a null fringe if the object has not moved.

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Photography: Holography, Viewing

The picture on the right is a photograph, taken against a diffuse light background, of a hologram recorded on photographic emulsion. The area shown is about 8mmx8mm. The holographic recording is the random variation in intensity which is an objective speckle pattern, and not the regular lines which are likely to be due to interference arising from multiple reflections in the glass plate on which the photographic emulsion is mounted. It is no more possible to discern the subject of the hologram from this than it is to identify the music on a gramophone record by looking at the structure of the tracks. When this hologram is illuminated by a divergent laser beam, the viewer will see the object used to make it (in this case, a toy van) because the light is diffracted by the hologram to re-construct the light which was scattered from the object.

When you look at a scene, each eye captures a portion of the light scattered from the scene, and the lens of the eye forms an image of the scene on the retina, in which light from each angular position is focused to a specific angular position in the image plane. Since the hologram reconstructs the whole of the scattered light field which was incident on the hologram, the viewer sees the same image whether this is derived from the light field scattered from the object, or the reconstructed light field produced by the hologram and is unable to tell whether he/she is looking at the real or the virtual object. If the viewer moves about, the object will appear to move in exactly the same way whether he/she is looking at the original light field or the reconstructed light field. If there are several objects in the scene, they will exhibit parallax. If the viewer is using both eyes (stereoscopic vision), he/she will get depth information when viewing the hologram in exactly the same way as when he/she is viewing the real scene.

It should be clear from this why a hologram is not a 3D photograph. A photograph records an image of the recorded scene from a single viewpoint, which is defined by the position of the camera lens. The hololgram is not an image, but an encoding system which enables the scattered light field to be reconstructed. Images can then be formed from any point in the reconstructed beam either with a camera or by eye. It was very common in the early days of holography to use a chess board as the object, and then take photographs at several different angles using the reconstructed light to show how the relative positions of the chess-pieces appeared to change.

Since each point in the hologram contains light from the whole of the original scene, the whole scene can, in principle, be re-constructed from a single point in the hologram. To demonstrate this concept, you can break the hologram into small pieces and you can still see the entire object from each small piece. If you envisage the hologram as a ‘window’ on the object, then each small piece of hologram is just a part of the window from which you can still view the object even if the rest of the window is blocked off.

You do, however, lose resolution as you decrease the size of the hologram – the image becomes ‘fuzzier’. This is a result of diffraction and arises in the same way as the resolution of an imaging system is ultimately limited by diffraction where the resolution becomes coarser as the lens or lens aperture diameter decreases.

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