By S J PRAKASH
Digital camera
Designed specifically for capturing digital images, and therefore one of the basic tools for anyone serious about electronic photography. Resolution levels on the latest models mean that it is possible to produce prints of photographic quality, and increasing levels of specification mean you don’t have to miss out on useful features available on conventional cameras.
What to consider
Digital cameras come in a wide range of specifications and prices, so you need to think carefully about what your needs are before parting with your hard-earned cash. These are the kind of issues you should be considering when you come to make a purchase:
- What resolution do you need?
- is a fixed lens sufficient or will a zoom
- Be required – and if so, what range?
- which is the most suitable removable
- Storage system?
- The lens
Many digital cameras feature a fixed lens with a slightly wide-angle focal length. (If you are serious in learning photography it’s worth spending a little extra for a zoom lens which allows you more versatility in framing the subject.)
Exposure/flash
Most digital cameras are fully automatic, taking care of exposure for you – though some models do offer an over-ride should you need to tweak the results. Usually there’s a built-in flashgun which fires as and when required, once again with some degree of user control which produce an electrical charge proportional to the amount of light that falls on them. Each pixel is a tiny part of the picture, and the total number in the array determines the resolution of the final image.
LCD monitor
Virtually all digital cameras now have a colour LCD monitor which shows you what the lens is seeing. It also allows you to check images already captured and delete them if you don’t like them. Some screens are difficult to view in bright light, so check before you buy. Some models have an optical viewfinder in addition to a LCD monitor, which makes them more versatile.
What is a CCD?
Digital cameras record images differently to conventional cameras. The image is captured by a CCD (Charge-Coupled Device).
Image quality
One of the key factors in image quality is resolution, which is indicated by the number of pixels captured by the CCD. The more pixels, the better the picture. Technology in this area is constantly improving, but most of the models available now deliver more than acceptable quality.
How Digital Images are Made Up
Changing from conventional photography to digital imaging means that your unit of currency changes too. Whereas film-based pictures are made up of tiny grains of silver halide, digital images consist of minute squares of colour and brightness called picture elements – or pixels. In simple terms, the more pixels you have the more detailed the image will be which is why the resolution of digital cameras and scanners is all-important.
The number of pixels you have determines the sharpness and detail in the image, whether you view on screen or print it out. The more you blow up the image, the more visible the pixels themselves become. If you go too far, the image will ‘pixel late’ and look un sharp. Having ‘surplus’ pixels in an image means that you can, if you wish, enlarge it without any loss of quality.
How pixels make up a digital image
When you digitize an image, it’s rather like placing a wire mesh over it and analyzing the brightness and colour of each square. Here’s what happens as you increase the number of pixels.
Understanding resolution There’s often confusion, even among experienced digital-imaging enthusiasts, about resolution. The complications seems to arise when photographers try to link the input resolution, from a digital camera, scanner, CD etc, to the output resolution requirements of an inkjet printer, computer monitor or reprographics company.
Once the picture has been saved onto the computer you can open it in your image-manipulation program and, if necessary, adjust the resolution according to the intended use. This will change the image size, making it smaller if resolution is increased and larger if resolution is decreased. Below is a guide to output resolutions.
1 x 1 pixel resolution If you take a typical picture and integrate all of the colors and the brightness, this is what you get – a 1 x 1 pixel image.
2 x 2 pixel resolution Once you get up to four pixels, you can begin to see variations in the colour and brightness but little detail.
4 x 4 pixel resolution Move up to 16 pixels and more tonality starts to emerge -though it’s still not possible to recognize the subject.
8 x 8 pixel resolution With 64 pixels visible there’s much more variation in colour and brightness, but we still can’t see what’s happening.
16 x 16 pixel resolution Now we have 256 pixels to play with shapes are starting to appear, but they continue to lack clear definition.
64 x 64 pixel resolution Once you get to 64 x 64 pixels, a total of 4,096, the people are more clearly defined – but the effect is a little coarse.
128 x 128 pixel resolution Not exactly photographic quality yet, but having 16,384 pixels (a 48 Kb image) begins to look acceptable.
256 x 256 pixel resolution Now a 192 Kb image containing 65,536 pixels, the image looks sharp and clear, with no individual pixels visible.
512 x 512 pixel resolution A 512 x 512 resolution gives 250,000 pixels, a 758 Kb file, and an image of photographic quality at modest size.
Which resolution?
Deciding which resolution to save an image at depends on what you eventually want to do with the pictures. Here are some examples of types of usage and the appropriate output resolution:
USE recommended output resolution
Screen use 72 to 75 *dpi
Inkjet printer 140 to 240 *dpi
Reproduction in magazine or book 240 to 300 *dpi
NEXT: Taking Better pictures
The Sinbad Classic to be held in February 19-21, 2009, in Muscat is billed as Arabia’s premier Sport Fishing Tournament, held under the auspices of the Minsitry of Tourism and Ministry of Sports Affairs. It is organised by Intevents, the event management arm of OITE, and is held with the support of Marina Bander Al Rowdha. 
Strangely, the first step in house building for Elsa Zaldivar is growing a vegetable used for bath sponges. She and Teodora Arguello, head of an association of sponge growers encourage rural women to grow high-quality loofahs. What to do with material left after creating the bath products led Zaldivar to combine the waste with recycled plastic to make panels for inexpensive housing. 
