Mechanics and Construction
By: Robert H. Walker
The camera is defined as a electro-mechanical device and an apparatus for taking pictures or photographs, or electronic digital images. The camera is basically a lightproof housing through which light is reflected off an object or a subject and an image is focused and recorded on a digital sensor or on photographic film through a lens that focuses the light.
There are many different camera types that are being used today:
35 mm Film
Medium Format
Large Format
Digital Imaging
all cameras are more or less advanced variations of the very first camera
Nearly all cameras are made up of the same basic components:
Camera body (the lightproof box)
Camera lens and a shutter to control the amount of light reaching the light-sensitive medium (Digital or Film)
Camera viewfinder to look at the scenic view that you wish to shoot
Focusing mechanism be it fixed or variable
Still Cameras
Focus and Composition of the Scene:
All cameras use a glass or plastic lens for the focusing of the light to take an image, except for pinhole cameras, which focus the image on the film through a tiny hole. The focal length of a lens, i.e., the distance between the rear of the lens (when focused on infinity) and the film, determines the angle of view and the size of objects as they appear on the film or digital imaging sensor. The light projected image is focused on the digital image sensor or the film by adjusting the distance between the lens and the electronic media or light sensitive film.
In most 35-mm cameras, this is done by rotating the lens which adjusts the focal length. With twin-lens reflex and larger view cameras, the whole lens and the panel are moved closer to or further away from the film. To view a subject for composing a picture, almost every camera has some kind of a viewfinder. Modern 35-mm single-lens reflex SLR cameras place the viewfinder screen in a special housing on the top of the camera body.
On the inside of the SLR camera there is a movable mirror that reflects the image from the lens to the viewfinder screen for viewing and focusing. As you prepare to take the picture it then flips out of the way when the shutter is tripped, so that the image hits the film or the digital sensor instead of the imaging viewing mirror. The mirror for the viewfinder will automatically return to its place after the exposure has been made.
Range finding cameras causes the object to be viewed by two separate windows; one views the subject scene directly and the other window contains an adjustable optical mirror device. When this device is adjusted by rotating the lens, the image entering through the lens can be brought into display with the image from the direct view focusing the object on the film. This range finding technique has been used since WWII in submarines and military applications for close estimations of distances of targets. It is very accurate for optics and is slowly being replaced with laser rangefinder's in military applications where tolerances are very tight.
Controlling the Amount of Light Entering into the Camera Body
The maximum opening in the lens through which light enters the camera will indicate the speed of a lens. The speed of the lens is controlled by an iris (eye) diaphragm.
The iris of a camera acts the same like the iris, the dark part of your eye, and it is a set of metal blades that form a circular hole in the center area at the base of the lenses and whose diameter can be made larger or smaller. The shutter controls the amount of time that light is allowed to enter your camera.
There are two basic types of shutters:
Leaf-type
Focal-plane.
The leaf-type shutter uses a ring of overlapping metal blades, which are similar to those of the iris diaphragm. It is usually placed between the lens elements, but sometimes it is placed behind or in front of the lens. The focal-plane shutter is located just in front of the film or digital imaging sensor plane and has one or two cloth or metal curtains that travel vertically or horizontally across the film frame. By adjusting the shutter speed, the proper amount of light needed for a good exposure can be obtained.
Features of Modern Film and Digital Cameras
Most of today's 35-mm cameras incorporate a rapid film-transport mechanism, lens interchangeability, and a built-in light meter. All digital cameras have built in light metering capability. Many also have an automatic exposure device where the shutter speed is regulated automatically to produce the "correct" exposure. Accessories include filters, which correct for deficiencies in film sensitivity; flash bulbs and flash mechanisms for supplying light; and monopods and tripods, for steady support.
Range finding cameras causes the object to be viewed by two separate windows; one views the subject scene directly and the other window contains an adjustable optical mirror device. When this device is adjusted by rotating the lens, the image entering through the lens can be brought into display with the image from the direct view focusing the object on the film. This range finding technique has been used since WWII in submarines and military applications for close estimations of distances of targets. It is very accurate for optics and is slowly being replaced with laser rangefinder's in military applications where tolerances are very tight.
Controlling the Amount of Light Entering into the Camera Body
The maximum opening in the lens through which light enters the camera will indicate the speed of a lens. The speed of the lens is controlled by an iris (eye) diaphragm.
The iris of a camera acts the same like the iris, the dark part of your eye, and it is a set of metal blades that form a circular hole in the center area at the base of the lenses and whose diameter can be made larger or smaller. The shutter controls the amount of time that light is allowed to enter your camera.
There are two basic types of shutters:
Leaf-type
Focal-plane.
The leaf-type shutter uses a ring of overlapping metal blades, which are similar to those of the iris diaphragm. It is usually placed between the lens elements, but sometimes it is placed behind or in front of the lens. The focal-plane shutter is located just in front of the film or digital imaging sensor plane and has one or two cloth or metal curtains that travel vertically or horizontally across the film frame. By adjusting the shutter speed, the proper amount of light needed for a good exposure can be obtained.
Features of Modern Film and Digital Cameras
Most of today's 35-mm cameras incorporate a rapid film-transport mechanism, lens interchangeability, and a built-in light meter. All digital cameras have built in light metering capability. Many also have an automatic exposure device where the shutter speed is regulated automatically to produce the "correct" exposure. Accessories include filters, which correct for deficiencies in film sensitivity; flash bulbs and flash mechanisms for supplying light; and monopods and tripods, for steady support.
Simple box cameras are fixed-focus cameras with limited or no control over exposure. Twin-lens reflex cameras use one lens solely for viewing while the other focuses the image on the film. Other popular cameras are compact 35-mm rangefinding cameras, 126 cartridge cameras, and the sub miniature cameras, which uses 9.5-mm film. Digital cameras use Photoshop for filters quite often and have the most advanced features, in my opinion.
Development of the Camera
Some claim that the very first camera was invented during the times of the Greeks, others say an Arabic man invented this camera. It was basically a dark box large enough for the viewer to stand inside; with a small hole in one side. An inverted (upside down) image of a scene was shown on the inside of the darkroom. An artist then traced the image and this was considered the origin of the camera obscura. The first diagram of a camera appeared in a manuscript written by Leonardo da Vinci in 1519, even though he did not claim the invention as his own. Joseph Nicéphore Niépce first achieved the recording of a negative image on a light-sensitive material in 1826. He coated a piece of paper with asphalt and exposed it to light on the inside the camera for eight hours. This was not practical for portraits of people as they could not stand still for that long and the image would be blurred. So buildings were the first images recorded with these types of devices. Even though different kinds of devices for making pictures had been invented as early as the 1860s, E. J. Marey built the first motion picture camera in 1887. In 1889 the great scientist and inventor Thomas Edison invented the first successful camera. However, cinematography was not accessible to amateurs until 1923, when Eastman Kodak produced the first 16-mm safety film. Bell & Howell introduced cameras and projectors that used 16-mm reversal safety film.
Sources:
The Encyclopedia of Photography (1971);
The Focal Encyclopedia of Photography (1972);
The Duenow.com website;
Howstuffworks.com
Development of the Camera
Some claim that the very first camera was invented during the times of the Greeks, others say an Arabic man invented this camera. It was basically a dark box large enough for the viewer to stand inside; with a small hole in one side. An inverted (upside down) image of a scene was shown on the inside of the darkroom. An artist then traced the image and this was considered the origin of the camera obscura. The first diagram of a camera appeared in a manuscript written by Leonardo da Vinci in 1519, even though he did not claim the invention as his own. Joseph Nicéphore Niépce first achieved the recording of a negative image on a light-sensitive material in 1826. He coated a piece of paper with asphalt and exposed it to light on the inside the camera for eight hours. This was not practical for portraits of people as they could not stand still for that long and the image would be blurred. So buildings were the first images recorded with these types of devices. Even though different kinds of devices for making pictures had been invented as early as the 1860s, E. J. Marey built the first motion picture camera in 1887. In 1889 the great scientist and inventor Thomas Edison invented the first successful camera. However, cinematography was not accessible to amateurs until 1923, when Eastman Kodak produced the first 16-mm safety film. Bell & Howell introduced cameras and projectors that used 16-mm reversal safety film.
Sources:
The Encyclopedia of Photography (1971);
The Focal Encyclopedia of Photography (1972);
The Duenow.com website;
Howstuffworks.com
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Pinhole Cameras
The definition of a pinhole camera is a camera without any kind of a lens. Lenses in a good camera are usually constructed of glass or in the inexpensive cameras lenses are usually made of clear plastic. The pinhole camera does not use anything for a lens. These were the very first original cameras made in the history of photography. The very first pinhole cameras were not even loaded with film and only projected an image in a dark room with the light from the outside coming in through the pinhole. This is the origin of film stills photography.
The image in a pinhole camera is inverted or upside down on the area that the image in projected. The wikipedia has an excellent article about this and an image to explain this and a picture is worth a thousand words. I have the Wiki link at the bottom of this article.
I built a pinhole camera for observing a solar eclipse when I was a child and you can safely watch the image of the moon as it crosses the path of the sun. These types of devices were originally called camera obscura and it is a Latin word meaning "dark chamber" and this is where we get the word darkroom. Before the advent of film, artists would trace the images projected through the pinhole as a more permanent record. Later on metal plates with various silver compounds would be used to record the image and were the ancestors of what would become film photography, these metal plates used to record images are generally credited to Louis Daguerre.
The basic tenets and principles of the camera obscura have been known for over one thousand years. Some claim that Ibn al-Haitham (Al-Hazen) had constructed a functional camera obscura in the 10th century. Its was used as a drawing aid and could very well have been used by familiar artists by as early as the 15th Century, Leonardo da Vinci described a type of the camera obscura in his Codex Atlanticus writings. Such cameras were later built and used by William Fox Talbot and Louis Daguerre, a French inventor, for creating the very first photographs.
The image in a pinhole camera is inverted or upside down on the area that the image in projected. The wikipedia has an excellent article about this and an image to explain this and a picture is worth a thousand words. I have the Wiki link at the bottom of this article.
I built a pinhole camera for observing a solar eclipse when I was a child and you can safely watch the image of the moon as it crosses the path of the sun. These types of devices were originally called camera obscura and it is a Latin word meaning "dark chamber" and this is where we get the word darkroom. Before the advent of film, artists would trace the images projected through the pinhole as a more permanent record. Later on metal plates with various silver compounds would be used to record the image and were the ancestors of what would become film photography, these metal plates used to record images are generally credited to Louis Daguerre.
The basic tenets and principles of the camera obscura have been known for over one thousand years. Some claim that Ibn al-Haitham (Al-Hazen) had constructed a functional camera obscura in the 10th century. Its was used as a drawing aid and could very well have been used by familiar artists by as early as the 15th Century, Leonardo da Vinci described a type of the camera obscura in his Codex Atlanticus writings. Such cameras were later built and used by William Fox Talbot and Louis Daguerre, a French inventor, for creating the very first photographs.
These types of cameras were used originally to photography fixed objects, like buildings, as they had a very long exposure time. Sometimes hours were required for the exposure and this was far too long to take an image of someone as they would move and the image would be blurred. This problem was solved by new chemical solutions for the recording of the images and by having the subject of the portrait put their head into a type of brace to prevent movement.
If you want to be a pinhole photographer then all you must do is build a home made do it yourself pinhole camera. The pinhole camera is very good with perspective as there is no lens distortion to content with. The hole should be perfectly round and the size of the hole is very important in the construction of the camera. The depth of field is in a pinhole camera is basically infinite. This does not necessarily mean that everything will be in proper focus. The distance from the aperture of the camera and to the film plane in relation to the infinite depth of field will determine if everything is in focus or out of focus.
The f-stop is very important to the function of the camera. The f-stop of the pinhole camera may be computed and calculated by dividing the diameter of the circular pinhole into the focal length of the pinhole camera. The diameter of the pinhole can be determined by knowing the diameter of the pin, needle or drill bit used to make the pinhole. The definition of the focal length is the distance from the pinhole to the film.
Basically you take a box or any container punch a pinhole and then attach film to the opposite end and then you have your camera. If you wish to be a pinhole photographer then you should see the following websites for more information.
See the Wiki article here: http://en.wikipedia.org/wiki/Pinhole_camera
Excellent advice on making the pinhole camera here: http://www.mrpinhole.com/
There is a world pinhole camera day: http://www.pinholeday.org/gallery/index.php
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