There are two people credited with the use of the word ‘photography’. Johann von Maedler and Sir John Herschel. Both of them used the word in 1839. Johann used the word in a newspaper article on February 25th and Sir John used it at a Royal Society lecture on March 14th. The word comes from Greek meaning ‘light’ and ‘drawing’.
2. Who created the first camera obscura?
The first description of the construction of a camera obscura was by Ibn al-Haytham in his 1021 AD ‘Book of Optics’. However, there were earlier references to pin hole cameras. The Chinese made reference to them as early as approximately 400 BC and also Aristotle did approximately 350 BC.
3. Draw a diagram showing how a pin-hole camera works.
4. Who was the person responsible for the first permanent camera image?
The first permanent camera image was made by Nicephore Niepce in 1826. He used a camera obscura and the image was captured on a pewter plate coated with bitumen of Judea. The image took eight hours to make and is reproduced below.
View from upper window of Nicephore Niepce’s house – Nicephore Niepce 1826
5. What are two ways to control the amount of exposure of a photograph?
Aperture – This controls the iris of the lens making it either a large aperture or small aperture. Aperture is measured by f-stops – a large f-stop is a small aperture and a small f-stop is a large aperture. When an f-Stop is halved e.g. F16 to F8, the amount of light allowed through the lens is four times what it was. Aperture also controls depth of field.
Shutter speed – This controls the time the shutter is open allowing light to the film or sensor. Shutter speed also has other impacts on a photograph. A slow shutter speed will cause blurring of motion whereas a high shutter speed can freeze action.
6. Name two shutter types and briefly explain how they operate.
Two shutter types are the leaf shutter and the focal plane shutter.
Leaf shutter – A leaf shutter is made up of overlapping blades with a timing mechanism to open and close them. They are normally located within the lens and do not offer very high shutter speeds due to their mechanical limits.
Focal plane shutter – the focal plane shutter consists of a first and second curtain that moves across the focal plane of a camera. As the second curtain follows the first, very fast shutter speeds can be achieved. Older cameras had a horizontally moving curtain whereas most modern cameras have a vertical moving curtain (normally metal blades).
7. What is an f-stop?
An f-stop is the focal length of a lens divided by the diameter of the iris (or lens opening). A halving of an f-stop allows four times as much light into the lens. A normal f-stop scale e.g. f2.8, f4, f5.6, f8, f11, f16 etc. has two times more or less light per stop. Fast lenses have small f-stops as their largest aperture e.g. f1.4 whereas slow lenses have larger numbers as their largest aperture e.g. f5.6
8. What is an f-number?
An f-number is the numerical representation of an f-stop – the same thing really.
9. What does exposure mean?
Exposure is the amount of light that is captured by the film or sensor and is controlled by shutter speed, aperture and ISO. Exposure controls how light or dark an image is.
10. If exposure = time x intensity, what does time stand for and what does intensity stand for? (hint look at question 5)
Time is controlled by the shutter speed and is the amount of time the film or sensor is exposed to light. Intensity is the amount of light reaching the film or sensor and is controlled by the aperture (f-stop) and brightness of the subject.
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