Digital Photography:
In the early days - less than ten years ago, digital cameras were very expensive and of little practical use in the production of quality photographic images. Today they are comparatively cheap and capable of exceeding film in the quality of the image they create, and faster and more flexible in use. Digital image capture has already replaced film in most sectors and will continue to make 'inroads' into film sales.
Advantages of Digital Photography:
In traditional photography the film is exposed in the camera and then has to be processed and printed. This means that it has to be taken to a photographic lab. To be economical the film has to be finished before it is processed which may mean taking 36 pictures.
In digital photography an individual image can be taken and downloaded to computer.
Depending on the final image you require it is possible to carry out the complete process on a standard computer and printer, avoiding the need to use a lab. You also save on the cost of buying film.
For professional photographers it is an advantage to have a digital original image as previously images from film required scanning before they could be used in publication.
Other advantages of digital photography lie in the colour technology available in cameras. Colour photography on film is dependant on the light source. Most film is designed for use in daylight and filters have to be used under artificial light. Digital cameras can be controlled to work under most of the common artificial light sources without need for further correction.
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Technical specifications of Cameras
The design of digital cameras has generally followed that of their film counterparts.
The majority are similar in design and use to film based compact cameras, having a viewfinder. usually situated above the lens which takes the picture or increasingly commonly having no viewfinder - expecting you to use the screen on the back of the camera to compose your picture.
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The other type are digital S.L.R. cameras.
These work in ways very similar to 'traditional' S.L.R. cameras.
The cost is generally much higher than the cost of compact types. Compact digital cameras can now be purchased from £50, S.L.R. cameras from about £300.
Technical information on sensor sizes
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The first consumer digital camera was launched in 1981 and the first digital SLR in 1986 but they have been in general use for less than 10 years. The pace of development is still high, last year Canon introduced over 20 new cameras. The average production run of a compact digital camera lasts about 1 year, and digital S.L.R. cameras about 18 months.
The quality of images obtained from digital cameras is determined by a number of factors, but the most important is the file size that the camera captures. This is usually measured in megapixels.
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Without manipulation, the size of high quality prints available from cameras is approx. as follows:
1 megapixel 4"x 3".
2 megapixel 5.5" x 4"
3 megapixel 6.5" x 5"
4 megapixel 7.5" x 5.5"
5 megapixel 8.5" x 6.5"
6 megapixel 10" x 6.7"
8 megapixel 11" x 8"
10 megapixel 13" x 8.5"
12 megapixel 15" x 10"
Images can usually be interpolated to twice the size without noticeable loss of quality.
e.g. 4 megapixel from 7.5"x 5.5" to 11"x 7.5"
or 6 megapixel from 10" x 6.7" to 15" x 10"
Increasing image size beyond this requires careful manipulation and some loss of quality should be expected.
Printing using 'rip' software can double the size again.
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