Photography

Thursday, September 9, 2010

Digital photography

A handheld digital camera, Canon Ixus class.

Olympus E-420 Four Thirds entry-level DSLR.

The Nikon D1, the first DSLR to truly compete with, and begin to replace, film cameras in the professional photojournalism and sports photography fields.

Nikon DSLR and scanner, which converts film images to digital

Sony Ericsson K800i camera phone.

Manual shutter control and exposure settings can achieve unusual results.

Main article: Digital photography

Traditional photography burdened photographers working at remote locations without easy access to processing facilities, and competition from television pressured photographers to deliver images to newspapers with greater speed. Photo journalists at remote locations often carried miniature photo labs and a means of transmitting images through telephone lines. In 1981, Sony unveiled the first consumer camera to use a charge-coupled device for imaging, eliminating the need for film: the Sony Mavica. While the Mavica saved images to disk, the images were displayed on television, and the camera was not fully digital. In 1990, Kodak unveiled the DCS 100, the first commercially available digital camera. Although its high cost precluded uses other than photojournalism and professional photography, commercial digital photography was born.

Digital imaging uses an electronic image sensor to record the image as a set of electronic data rather than as chemical changes on film. The primary difference between digital and chemical photography is that chemical photography resists manipulation because it involves film and photographic paper, while digital imaging is a highly manipulative medium. This difference allows for a degree of image post-processing that is comparatively difficult in film-based photography and permits different communicative potentials and applications.

Digital point-and-shoot cameras have become widespread consumer products, outselling film cameras, and including new features such as video and audio recording. Kodak announced in January 2004 that it would no longer sell reloadable 35 mm cameras in western Europe, Canada and the United States after the end of that year. Kodak was at that time a minor player in the reloadable film cameras market. In January 2006, Nikon followed suit and announced that they will stop the production of all but two models of their film cameras: the low-end Nikon FM10, and the high-end Nikon F6. On May 25, 2006, Canon announced they will stop developing new film SLR cameras. Though most new camera designs are now digital, a new 6x6cm/6x7cm medium format film camera was introduced in 2008 in a cooperation between Fuji and Voigtländer.^[18]^[19]

According to a survey made by Kodak in 2007, 75 percent of professional photographers say they will continue to use film, even though some embrace digital.

According to the U.S. survey results, more than two-thirds (68 percent) of professional photographers prefer the results of film to those of digital for certain applications including:

film’s superiority in capturing more information on medium and large format films (48 percent);
creating a traditional photographic look (48 percent);
capturing shadow and highlighting details (45 percent);
the wide exposure latitude of film (42 percent); and
archival storage (38 percent)

Digital imaging has raised many ethical concerns because of the ease of manipulating digital photographs in post processing. Many photojournalists have declared they will not crop their pictures, or are forbidden from combining elements of multiple photos to make "illustrations," passing them as real photographs. Today's technology has made picture editing relatively simple for even the novice photographer. However, recent changes of in-camera processing allows digital fingerprinting of RAW photos to verify against tampering of digital photos for forensics use.

Camera phones, combined with sites like Flickr, have led to a new kind of social photography.

Colour and Black &White Photography

Black-and-white

Color

Main article: Color photography

Color photography was explored beginning in the mid 1800s. Early experiments in color could not fix the photograph and prevent the color from fading. The first permanent color photo was taken in 1861 by the physicist James Clerk Maxwell.

Early color photograph taken by Prokudin-Gorskii (1915).

One of the early methods of taking color photos was to use three cameras. Each camera would have a color filter in front of the lens. This technique provides the photographer with the three basic channels required to recreate a color image in a darkroom or processing plant. Russian photographer Sergei Mikhailovich Prokudin-Gorskii developed another technique, with three color plates taken in quick succession.

Practical application of the technique was held back by the very limited color response of early film; however, in the early 1900s, following the work of photo-chemists such as H. W. Vogel, emulsions with adequate sensitivity to green and red light at last became available.

The first commercially successful color process, the Autochrome, invented by the French Lumière brothers, reached the market in 1907. It was based on a 'screen-plate' filter made of dyed grains of potato starch, and was one of many additive color screen products available between the 1890s and the 1950s. The presumably final use of the additive screen process for color photography on film was Polachrome, an "instant" 35 mm slide film introduced in the mid-1980s and discontinued in the mid-2000s. In 1935, American Kodak introduced the first modern ('integrated tri-pack') color film which was developed by two musicians Leopold Mannes and Leopold Godowsky ("Man" and "God") working with the Kodak Research Labs. It was Kodachrome, based on multiple layered silver gelatin emulsions that were each sensitized to one of the three additive colors—red, green, and blue. The cyan, magenta, and yellow dyes were created in those layers by adding color couplers during processing. This was followed in 1936 by Agfa's Agfacolor Neu. Unlike the Kodachrome tri-pack process, the color couplers in Agfacolor Neu were incorporated into the emulsion layers during manufacture, which greatly simplified the film processing. Most modern color films, except Kodachrome, use such incorporated-coupler techniques, though since the 1970s nearly all have used a technique developed by Kodak to accomplish this, rather than the original Agfa method. Instant color film was introduced by Polaroid in 1963.

Color photography may form images as a positive transparency, intended for use in a slide projector, or as color negatives intended for use in creating positive color enlargements on specially coated paper. The latter is now the most common form of film (non-digital) color photography owing to the introduction of automated photoprinting equipment.

Beginning Photography Tips

As a beginning photographer, it is easy to get discouraged when your pictures come out too dark or constantly blurry. It's easy for the beginning photographer to quickly become overwhelmed; especially when professionals are spouting off terms like shutter speed and aperture. However, with a little more understanding, and a little practice applying those terms, the beginning photographer can quickly and easily be on their way to capturing that perfect picture. Here are the most common photography terms and some helpful hints for applying them in your photography.

Shutter Speed refers to the amount of time that the shutter is open and light strikes the CCD (Charge Coupled Devices). This device converts the light entering through the lens into electric signals and creates the digital image. Shutter speed can be adjusted along with the aperture to more effectively capture the subject image. Slower shutter speeds means that the shutter is open longer and more light is getting in. Try shooting a few pictures of water like waterfalls, rivers, and fountains using a slow shutter speed. This effect can enhance water images. Faster shutter speeds means less light is getting in. This can create a freezing effect on fast moving objects. Try shooting some action shots at your favorite sporting event with a faster shutter speed.

The Aperture works in correlation with the shutter speed. Often referred to as the aperture value (AV) it increases or reduces the thickness of the light beam passing through the lens to the CCD. Opening the aperture reduces the AV and closing the aperture increases the AV. The best place to experiment with AV is in the garden. Open the aperture and focus on a flower. The objects around the flower (closer and farther than the focused subject) will be more out of focus, emphasizing only the flower. Now close the aperture while focusing on the same flower. The range of your focus expands forward and backward allowing for the objects around the flower to remain in focus.

A common enemy to the beginning photographer is Camera Shake (Blur). This is pretty self explanatory. It is when the camera moves while the shutter is open creating a blurred image. Often times adjusting to a higher shutter speed from a low one will solve this problem.. If that doesn't work, try raising the aperture as well and be sure to use a flash. If your images are still blurry you may need a tripod to capture a clear image. Most of the newer digital and DSLR cameras on the market come equipped with anti-shake features to help combat this problem, but it's good to know what causes it and how to fix things if you have an older model camera.

As one beginning photographer to another, don't let the terminology scare you. By just doing a little bit of reading and some experimenting with different settings on your camera, most obstacles can soon be overcome. It is a bit of a trial and error process, but when you capture a picture of your daughter mid-air, hair standing up, grinning from ear to ear, as she jumps rope, it all becomes worth it.

Brief history of photography

The word photography derives from the Greek words, light and graphein (to draw). The method of recording images using the action of light onto a sensitive material.

Around 330 BC, Aristotle pondered on the question... why the sun could make a circular image when it shined through a square hole?

It was around 1000AD, when Alhazen invented the first pinhole camera, also known as a camera obscura.

In 1872, Joseph Niepce made the first photograph using a pinhole camera. Before this, people simply just used the pinhole camera for viewing or drawing. Joseph’s photographs were the starting point for the modern photographer by letting light draw the picture. Neicpe’s photographs however, were not yet advanced enough as they required 8 hours of light exposure to create. Soon after the image appeared, it would disappear almost straight away.

Daguerre inventor of the first practical process of photography went on to join with Neicpe in 1829 to develop his work.

In 1839, after several years of experimentation, and the death of Joseph Neicpe; Daguerre developed a better and more effective method of photography, and named it after himself ‘The Daguerreotype’. This involved fixing the image onto a sheet of silver plated copper, coating it in iodine, placing the plate in the camera and exposing it for a few minutes. After the image was exposed to the light, the plate was then bathed in a solution of silver chloride, creating an image that lasted.

Shortly after this Daguerre sold the rights for the ‘Daguerreotype’ to the French government. By 1850 over 70 ‘Daguerreotype’ studios were opened up in New York City alone.

Henry Fox Talbot, an English botanist and mathematician; invented the first negative, meaning multiple positive prints could be made.
In 1841, he perfected the art of his invention and called it ‘The Calotype’, the Greek meaning for ‘beautiful picture.’

In 1879, since the discovery of tintypes and wet plate negatives, dry plate negatives were developed. This was a glass negative plate with a dried gelatine emulsion, allowing the ability of being stored for a longer period of time. There wasn’t any need for portable dark rooms, and because the dry process absorbed light so quickly, the hand held camera was now possible.

It was George Eastman in 1889, who invented the flexible roll film, this was a film with a base that was flexible, unbreakable and could be rolled.

By the early 1940’s, colour film was developed, using modern technology of dye coupled colours in which a chemical process connects the 3 dye layers together to create an apparent colour image.

Exposure and rendering

Camera controls are inter-related. The total amount of light reaching the film plane (the "exposure") changes with the duration of exposure, aperture of the lens, and on the effective focal length of the lens (which in variable focal length lenses, can force a change in aperture as the lens is zoomed). Changing any of these controls can alter the exposure. Many cameras may be set to adjust most or all of these controls automatically. This automatic functionality is useful for occasional photographers in many situations.

The duration of an exposure is referred to as shutter speed, often even in cameras that don't have a physical shutter, and is typically measured in fractions of a second. Aperture is expressed by an f-number or f-stop (derived from focal ratio), which is proportional to the ratio of the focal length to the diameter of the aperture. If the f-number is decreased by a factor of , the aperture diameter is increased by the same factor, and its area is increased by a factor of 2. The f-stops that might be found on a typical lens include 2.8, 4, 5.6, 8, 11, 16, 22, 32, where going up "one stop" (using lower f-stop numbers) doubles the amount of light reaching the film, and stopping down one stop halves the amount of light.

Image capture can be achieved through various combinations of shutter speed, aperture, and film or sensor speed. Different (but related) settings of aperture and shutter speed enable photographs to be taken under various conditions of film or sensor speed, lighting and motion of subjects and/or camera, and desired depth of field. A slower speed film will exhibit less "grain", and a slower speed setting on an electronic sensor will exhibit less "noise", while higher film and sensor speeds allow for a faster shutter speed, which reduces motion blur or allows the use of a smaller aperture to increase the depth of field. For example, a wider aperture is used for lower light and a lower aperture for more light. If a subject is in motion, then a high shutter speed may be needed. A tripod can also be helpful in that it enables a slower shutter speed to be used.

For example, f/8 at 8 ms (1/125th of a second) and f/5.6 at 4 ms (1/250th of a second) yield the same amount of light. The chosen combination has an impact on the final result. The aperture and focal length of the lens determine the depth of field, which refers to the range of distances from the lens that will be in focus. A longer lens or a wider aperture will result in "shallow" depth of field (i.e. only a small plane of the image will be in sharp focus). This is often useful for isolating subjects from backgrounds as in individual portraits or macro photography. Conversely, a shorter lens, or a smaller aperture, will result in more of the image being in focus. This is generally more desirable when photographing landscapes or groups of people. With very small apertures, such as pinholes, a wide range of distance can be brought into focus, but sharpness is severely degraded by diffraction with such small apertures. Generally, the highest degree of "sharpness" is achieved at an aperture near the middle of a lens's range (for example, f/8 for a lens with available apertures of f/2.8 to f/16). However, as lens technology improves, lenses are becoming capable of making increasingly sharp images at wider apertures.

Image capture is only part of the image forming process. Regardless of material, some process must be employed to render the latent image captured by the camera into a viewable image. With slide film, the developed film is just mounted for projection. Print film requires the developed film negative to be printed onto photographic paper or transparency. Digital images may be uploaded to an image server (e.g., a photo-sharing web site), viewed on a television, or transferred to a computer or digital photo frame.

A photographer using a tripod for greater stability during long exposure

Prior to the rendering of a viewable image, modifications can be made using several controls. Many of these controls are similar to controls during image capture, while some are exclusive to the rendering process. Most printing controls have equivalent digital concepts, but some create different effects. For example, dodging and burning controls are different between digital and film processes. Other printing modifications include:

Chemicals and process used during film development
Duration of print exposure – equivalent to shutter speed
Printing aperture – equivalent to aperture, but has no effect on depth of field
Contrast – changing the visual properties of objects in an image to make them distinguishable from other objects and the background
Dodging – reduces exposure of certain print areas, resulting in lighter areas
Burning in – increases exposure of certain areas, resulting in darker areas
Paper texture – glossy, matte, etc.
Paper type – resin-coated (RC) or fiber-based (FB)
Paper size
Toners – used to add warm or cold tones to black and white prints

Photography

Photography is the process, activity and art of creating still or moving pictures by recording radiation on a radiation-sensitive medium, such as a photographic film, or an electronic sensor. Photography uses foremost radiation in the UV, visible and near-IR spectrum. For common purposes the term light is used in stead of radiation. Light reflected or emitted from objects form a real image on a light sensitive area (film or plate) or a FPA pixel array sensor by means of a pin hole or lens in a device known as a camera during a timed exposure. The result on film or plate is a latent image, subsequently developed into a visual image (negative or diapositive). An image on paper base is known as a print. The result on the FPA pixel array sensor is an electrical charge at each pixel which is electronically processed and stored in a computer (raster)-image file for subsequent display or processing. Photography has many uses for business, science, manufacturing (f.i. Photolithography), art, and recreational purposes.

Lens and mounting of a large-format camera.

A historic camera: the Contax S of 1949 — the first pentaprism SLR.

Nikon F of 1959 — the first 35mm film system camera.

Late Production Minox B camera with later style "honeycomb"selenium light meter

A portable folding reflector positioned to "bounce" sunlight onto a model

As far as can be ascertained, it was Sir John Herschel in a lecture before the Royal Society of London, on March 14, 1839 who made the word "photography" known to the whole world. But in an article published on February 25 of the same year in an unknown and quite anonymous newspaper called the Vossische Zeitung, Johann von Maedler, a Berlin astronomer, used the word photography already. The word photography is based on the Greek φῶς (photos) "light" and γραφή (graphé) "representation by means of lines" or "drawing", together meaning "drawing with light"

Function

The camera or camera obscura is the image-forming device, and photographic film or a silicon electronic image sensor is the sensing medium. The respective recording medium can be the film itself, or a digital electronic or magnetic memory.

Photographers control the camera and lens to "expose" the light recording material (such as film) to the required amount of light to form a "latent image" (on film) or "raw file" (in digital cameras) which, after appropriate processing, is converted to a usable image. Digital cameras use an electronic image sensor based on light-sensitive electronics such as charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology. The resulting digital image is stored electronically, but can be reproduced on paper or film.

The movie camera is a type of photographic camera which takes a rapid sequence of photographs on strips of film. In contrast to a still camera, which captures a single snapshot at a time, the movie camera takes a series of images, each called a "frame". This is accomplished through an intermittent mechanism. The frames are later played back in a movie projector at a specific speed, called the "frame rate" (number of frames per second). While viewing, a person's eyes and brain merge the separate pictures together to create the illusion of motion.

In all but certain specialized cameras, the process of obtaining a usable exposure must involve the use, manually or automatically, of a few controls to ensure the photograph is clear, sharp and well illuminated. The controls usually include but are not limited to the following:

Control	Description
Focus	The adjustment to place the sharpest focus where it is desired on the subject.
Aperture	Adjustment of the lens opening, measured as f-number, which controls the amount of light passing through the lens. Aperture also has an effect on depth of field and diffraction – the higher the f-number, the smaller the opening, the less light, the greater the depth of field, and the more the diffraction blur. The focal length divided by the f-number gives the effective aperture diameter.
Shutter speed	Adjustment of the speed (often expressed either as fractions of seconds or as an angle, with mechanical shutters) of the shutter to control the amount of time during which the imaging medium is exposed to light for each exposure. Shutter speed may be used to control the amount of light striking the image plane; 'faster' shutter speeds (that is, those of shorter duration) decrease both the amount of light and the amount of image blurring from motion of the subject and/or camera.
White balance	On digital cameras, electronic compensation for the color temperature associated with a given set of lighting conditions, ensuring that white light is registered as such on the imaging chip and therefore that the colors in the frame will appear natural. On mechanical, film-based cameras, this function is served by the operator's choice of film stock or with color correction filters. In addition to using white balance to register natural coloration of the image, photographers may employ white balance to aesthetic end, for example white balancing to a blue object in order to obtain a warm color temperature.
Metering	Measurement of exposure so that highlights and shadows are exposed according to the photographer's wishes. Many modern cameras meter and set exposure automatically. Before automatic exposure, correct exposure was accomplished with the use of a separate light metering device or by the photographer's knowledge and experience of gauging correct settings. To translate the amount of light into a usable aperture and shutter speed, the meter needs to adjust for the sensitivity of the film or sensor to light. This is done by setting the "film speed" or ISO sensitivity into the meter.
ISO speed	Traditionally used to "tell the camera" the film speed of the selected film on film cameras, ISO speeds are employed on modern digital cameras as an indication of the system's gain from light to numerical output and to control the automatic exposure system. The higher the ISO number the greater the film sensitivity to light, whereas with a lower ISO number, the film is less sensitive to light. A correct combination of ISO speed, aperture, and shutter speed leads to an image that is neither too dark nor too light, hence it is 'correctly exposed,' indicated by a centered meter.
Autofocus point	On some cameras, the selection of a point in the imaging frame upon which the auto-focus system will attempt to focus. Many Single-lens reflex cameras (SLR) feature multiple auto-focus points in the viewfinder.

Many other elements of the imaging device itself may have a pronounced effect on the quality and/or aesthetic effect of a given photograph; among them are:

Focal length and type of lens (telephoto or "long" lens, macro, wide angle, fisheye, or zoom)
Filters placed between the subject and the light recording material, either in front of or behind the lens
Inherent sensitivity of the medium to light intensity and color/wavelengths.
The nature of the light recording material, for example its resolution as measured in pixels or grains of silver halide.