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Photographs make us stop and look at the world in a different way. They can make us focus in on a particular aspect of a subject, look at the familiar from an alternative viewpoint, enable us to see things we would never otherwise have the opportunity to see, and trigger a variety of emotional responses. Most of the time we see without really looking, we gather impressions and rarely stand and look or examine. Often we see what we want to see or what we expect to see rather than what is actually there!

Fast science, slow motion! High speed photography is the process of capturing a large number of images in a small amount of time. In this video, a special camera is used to capture images at around 2500 frames per second. This allows the subject to be played back 100 times slower than normal — something that takes one second to happen takes 100 seconds to play back. This allows observers to see phenomena which are normally too fast to observe.

Photography has been around for a very long time. The basic principle of the camera was in use a thousand years ago when Arab astronomers were projecting images of well lit objects onto the walls of darkened rooms. This so called camera obscura (dark room) was also documented by Leonardo da Vinci in 1519, and about this time it was being advocated as an aid to drawing. The image produced existed only while the light reflected from the object into the room.

It was not until 1826 that a record of the image was achieved when the first photographic image was produced on bitumen by Nicephore Niepce. It took an eight hour exposure and followed ten years of experimentation. Many better systems were suggested and in 1841 the process of photographic printing invented by W. H. Fox Talbot was patented, and introduced to the world as 'photogenic drawing'.

In 1850 albumen paper was invented for use in photography, and by 1894 a German paper company was using 60 000 fresh eggs a day.

Advances in chemistry and materials technology eventually led to the production of cameras able to take rolls of film (Leon Warnerke, 1875), and flexible negative films based on celluloid (John Carbutt, 1888).

In 1888 George Eastman produced the Kodak box camera with roll paper. Each roll took 100 photographs, but the camera and film had to be returned to the factory for developing, printing and reloading.

Photography fulfils a large number of purposes. For many it is used to capture moments and scenes that they wish to remember, and photographs produce family albums. It is important as an information tool to record details, and to record history.

The advent of moving pictures and then sound tracks revolutionised the entertainment industry!

In order to get some of the best shots, wildlife photographers sometimes need to get into precarious positions, so there can be an element of danger. However the danger now does not compare to the dangers associated with photography in its early days. Then, gun cotton dissolved in nitric acid was used to produce the emulsion ('film'), mercury vapours were given off by the developer and cyanide was a constituent of the fixer. The film used for early movies had a nitrocellulose base - flammable if not even explosive!

The word photograph comes from two Greek words - photos meaning light and graphein meaning to draw.

Without light there is no sight and no photographs of the type in this exhibition.

Light from objects enters the camera and hits the film while the shutter is open. This causes a chemical reaction. Developing and fixing the film involve further chemical reactions to produce the photograph itself.

Black and white photographic film is essentially composed of a layer of photographic emulsion on a thin plastic base, along with other layers that provide structure and protection.

The 'active ingredient' in the photographic emulsion is a silver halide that is sensitive to light. When exposed to light the silver halide crystals produce a latent image as they begin to break down into black specks of metallic silver. Developing the film completes the formation of silver to produce a negative of the picture.

A photographic print is made by allowing light to shine through the negative onto light sensitive photographic paper, usually through an enlarger.

Colour films contain three emulsion layers on a plastic base. Each of these layers is sensitive to a different colour of light - yellow, cyan and magenta.

Combinations of these three colours produce other colours.

Check out the parrot exhibit in the foyer to remind yourself!

Developers for colour films contain dye couplers which attach dyes to the silver that forms during the development of a colour film. The silver is then dissolved, leaving behind the dye.

In photography, the photographer has control over a number of variables. These determine the quality of a particular photograph.

The photographer obviously selects the subject. With wildlife photography it may be that many other variables are to an extent out of the control of the photographer. After all it is wild life. Patience is a definite virtue!

The variables that are under control are those relating to the camera, the film and lighting in terms of the situation and/or time of day selected for the photographing.

The camera

The controllable variables are the lens and its position, the aperture, the shutter speed and the use or otherwise of filters.

The lens, or more usually system of lenses is, designed to focus a clear image onto the film. A small inverted image of the picture is formed at the principal focus of the lens. Often the surfaces of the lenses are coated to reduce reflections. Different lens systems can be used to produce different types of photograph.

Short focal length lenses (eg 28 mm) are also called wide angle lenses since they can take in up to about 75 degrees and still bring it to focus on the film.

Long focal length lenses (eg 500 mm) are also called telephoto lenses. Cameras with these lenses need to be supported on a tripod!

Zoom lenses can be adjusted to a variety of different focal lengths. Spot them at the sports events!

In any particular situation, the amount of light reaching the film can be controlled through altering the shutter speed and the aperture or f stop.

(see Exposure time in the Taking photographs section)

The shutter speed is the length of time that the shutter stays open for to allow light into the camera.

The aperture is a direct control of the amount of light let into the camera - it controls the size of the hole that the light comes through.

In automatic cameras, altering the aperture (f stop) automatically controls the length of time for which the shutter is open so that the amount of light reaching the film is the correct amount for that type of film.

Explaining f stops

An f stop of f/2 or f2 means that the aperture (hole) diameter is half of the focal length of the lens.

An f stop of f/4 or f4 means that the aperture (hole) diameter is one quarter of the focal length of the lens.

Each time the diameter of the aperture is halved, it reduces the area (and so the amount of light passing through) by to one quarter. To get the same amount of light onto the film, the exposure to light would have to be four times as long, so the shutter speed would be four times as long.

In practice the fstops are determined so that going from one fstop to the next changes the aperture area (and therefore exposure) by a factor of two.

The usual f stops are f2, f2.8, f5.6, f8, f11, f16.

The f stop system was developed by the Royal Photographic Society of Great Britain and is a recognised standard. No matter where the lens is manufactured, no matter what the focal length of the lens, if it is set at f4 then it will let through the same amount of light, provided the lens is set to focus at infinity.

The aperture controls the amount of light entering the camera, but it has another important effect too; it alters the depth of field.

With a large aperture, only things at a particular distance from the lens will be in focus and the rest of the picture will be out of focus. This is a narrow depth of field.

With a small aperture, objects over a greater range of distances will be in acceptably sharp focus. This is a greater depth of field.

To understand why, consider the diagrams opposite. These show a point of light being photographed with the real focus just behind the film, using a large and a small aperture. Notice the size of the patch of film that is affected in each case

Exposure times can be linked to the f stops or they can be controlled manually.

The film

Films vary in the speed with which they respond to light

The silver halide crystals in film are also called grains, and they vary in size. They are mixed with gelatin to form a smooth mixture called the photographic emulsion.

The size of a grain in the emulsion determines how quickly that grain reacts to light, The smaller the grain, the higher the intensity of light it needs to be affected (exposed).

The comparative sizes of the grains in film emulsions determine how long it takes for them to be exposed, so we can get varying shades of grey, and also produce fast and slow films.

Fast films contain a range of grain sizes, but they are all large, so that the film responds quickly to light. Slow films by comparison have a range of small sized grains, and need a longer time to be affected!

The speed of a film is stated as an ISO number. ISO stands for International Standards Organisation.

The higher the number, the faster the film.

Combinations of film type and exposure time can be used to create different effects in photography. For example, very fast film and short exposure can be used to 'freeze' motion. Very fast film with longer exposure gives a slightly blurry picture that gives the impression of the movement.

The light

The light source itself and the shadows, reflections and patterns it produces can all contribute to a photograph, in content and in atmosphere.

If the source of light is small and close, then shadows formed are dark and have very well defined edges. This gives the photograph a hard quality. By comparison, if the source of light is large and distant and such as the sun, then the light has been diffused through clouds and reflected off surfaces and gives less well defined shadows. The picture has a much softer quality.

The position and number of light sources determines the number and direction of shadows and so impacts on the composition and mood of the picture.

Notice that the photographs in this exhibition all make the subject look really important and make you want to look closer.

This is achieved by good composition.

The photographs are uncluttered, they do not contain details that do not contribute to the real picture. You are forced to focus on the really important!

The frame

The edge of a photograph acts as a frame that does not really exist in nature, and can be used to produce shapes in the photograph shapes that are not really there.

When photographs are viewed, the viewer has no way of knowing what was actually there beyond the frame.

Try looking at photographs and imagining what else was there.

Try blocking off (major) portions of a photograph (or picture in a magazine) to make new, different pictures with a different focus!

Line

Good photographic design considers the dominant line and the overall arrangement of shapes within the photographic frame.

In black and white photographs, the line is a very important design feature.

The dominant line in a photograph may be a real line ( the horizon, telegraph wires), or it may be a 'line' formed by a number of elements within the picture.

Horizontal or vertical lines give stability to a picture, diagonal lines create a feeling of instability and so can make a picture more dynamic.

The dominant line of a picture may be a curve, and this is often arranged within a picture so that the viewers eye follows the curve in a natural way - starting at the top left and moving through to bottom right of the frame. The closer the curves come to the edges of the frame, the more dynamic the picture is as the eye movements need to be greater.

Positioning

Rarely is the focal point placed in the centre of the photograph. More often it is placed elsewhere, so encouraging the viewer's eye to move around the whole image and so look closer.

“Rules of composition” have been formulated to help create interesting and pleasing compositions. These 'rules' lead to good composition and produce designs that are harmonious and pleasing to the eye.

Angle

An unusual angle on a subject can encourage people to look closer. If a picture is the 'normal view', it may be dismissed as 'seen that before' unless there is something else that attracts the viewer in!

Often a high or low vantage point is used so that the background of the subject is changed from normal - the sky or the ground may provide an uncluttered background so that focus is on the subject even though the subject is 'normal view'.

Depth

A photograph is only a two dimensional representation of a three dimensional reality.

While our mind will often put back the three dimensionality, it can be aided in the composition by using perspective. Often points of interest are placed in the foreground, the middle distance and at distance! How many landscapes have tree foliage in the foreground?

Perspective lines (getting closer together implies distance) can also be reinforced by the placement of the subjects in the picture, so drawing the viewer from the outsides (foreground) towards the main subject at greater depth. This effect can also be achieved by using dark foreground tones, getting lighter at depth.

Colour also has an effect on how three dimensional a photograph appears. Warm colours like red and yellow seem to come forward, whereas the cool colours like blue seem to recede.

Exposure time

All photographs are pictures of moment(s) in time. By choosing appropriate lengths of time to capture moving subjects in a particular photograph, different effects can be achieved. Long exposures capture the subject in different parts of the motion and so appear blurry. This gives the impression of motion but gives less information about the subject itself. To give good information about the subject, the motion needs to be 'frozen' in time by using fast exposure. Much of the wildlife photography is high speed photography, freezing the action. Since the shutter is open for a very short period of time, little time is available for light to get into the camera, so lighting needs to be good and/or fast film used.

What the photographer has to do is determine the appropriate time!

If in a picture different things are moving at different speeds, it is possible to have the main subject appearing clear, but other moving things still appearing as a blur.

A technique that is sometimes used for action shots is called the slow sync flash technique, where slow shutter speed is used in dull light along with a flash to capture the main subject. This gives blurred background and sharp, recognisable main subject!

It is possible to keep the subject in motion in the picture for an extended period of time by using a slow shutter speed and panning and tracking the subject as it moves against the background and the background appears as a blur.

Other techniques that can be used to show movement include multiple exposure photographs, zooming in while the shutter is open, and manipulating the print during development stage.

Photography as an art is more than just merely pointing and shooting. These notes should provide you with enough information to understand some of the technical details.

The late Bill Germon's help was much appreciated during the writing of this information. For additional information, we have also included some internet addresses: