Monday, December 2, 2002		Feature

Roopinder Singh

HER husband lives in Liberia, her daughter is studying in college in the USA, and she is now in Chandigarh. How would Balreet keep them in touch with what’s happening? Through e-mail of course, you would say.

Right, but in addition to that she wants to convey so many things that can’t quite be described through words—her son’s smile after he got admission in his father’s alma matter, for example. That’s when she turns to a digital camera.

She uses one that costs not much more than conventional ones, but it has a significant advantage, you can take a photograph, view it immediately on the camera, delete it if you don’t like it and shoot again. Uploading the picture to your computer is almost instantaneous; no waiting for the film to finish, no developing delays, no scanning requirements—just click and transfer electronically and you have instant gratification.

Though digital cameras have been around for a while, they are now proliferating among computer users in India. It is fairly common to see such cameras being used at family occasions, to share memories with loved ones far away. The other day Rakesh came to our office twirling a camera attached to his key ring. What does he do with it? We didn’t even dare to ask.

Crystals vs pixels

The major difference between digital cameras and ordinary ones is that the image shot in the former is not saved on the film, but stored in electronic format.

Conventional cameras use a chemical process. A colour film basically consists of three layers of silver halide crystals that are sensitive to one third of the spectrum—red, green or blue. It has to be ‘developed’ through an elaborate chemical process for the image to come out in true colours.

In digital cameras, the image is saved on a charge-coupled device (CCD), which consists of an array of light-sensitive photocells. A photocell is sensitised by giving it an electrical charge prior to the exposure. The basic building block is a pixel, or a picture element, which is the smallest resolvable rectangular area of an image, either on a screen or stored in memory. In a colour picture, each pixel has its own brightness and colour, usually represented as red, green and blue intensities. These images are recorded electronically and can be transferred directly from cameras to other electronic devices such as computers.

Earlier when you wanted to send a photograph to someone through a computer, you had to scan, which essentially converted it into digital format, and then send it. Digital cameras help you bypass this.

Now that you are ready to consider digital cameras, what are the kinds you should look at? Well, like Balreet, most of us will be quite happy with the middle-level cameras that are in the Rs 20,000 range. Top professional cameras can cost as much as Rs 4.5 lakh. In comparing such cameras, the major parameters to look for are the image quality, exposure latitude and capacity for storage.

Image quality

The number of pixels it has determines the image quality. The middle-rung cameras these days have between two and three mega (million)-pixel resolution. They are more than adequate for home use and give beautiful results for prints around 5" x 7" or even larger. There are also cheaper cameras, like the one Rajesh has, with lower resolution, which are fine for sending e-mails or making small prints.

Professional cameras are six mega-pixels. All such cameras use image compression algorithms to compress images, so that repetitive information (like a white patch) is reduced and the memory space taken up is smaller. Image compression is necessary, but it can be overdone, affecting the quality of the image.

No doubt digital cameras have made impressive strides; however, there is nothing that can approach the quality of the good old film. But then, do you really need such high quality?

Storing the image

In conventional cameras, your images are stored on photographic films, of which particular kinds may be chosen for specific occasions. Thus you have ASA 100 film for bright daylight, and ASA 400 and above films for less light. Ideally, you would want the widest exposure latitude in your digital camera. Here again a mean of between ASA 100 and 200 would be fine for most situations.

In digital cameras your images are stored in removable flash memory and the cost of this has been going down steadily (get as much memory as you can afford). You can store the images in various file formats, though JPEG is the most commonly used. TIFF is a format used for print-quality images. The higher the resolution of the image, the larger the file size and lower the number of photographs that can be saved.

Playing around

Now that you have your camera, what can you do with it? You could, like Balreet, send pictures through e-mail, but that is just the beginning. You can really play around with images. There are many excellent programs included with most camera packages that allow you to easily cut out the not-required parts of pictures, make colour corrections, enlargements and manipulate images in other ways.

Macintosh as well as Windows XP systems have pulled out all stops to encourage digital photography. You can make digital photo albums after saving pictures from your camera on your computer. You can also print them on photo-quality printers, or have them commercially printed on photographic paper at a rupee or two more per print than the regular prints. Digital cameras open new dimensions.

As for those who can’t afford these cameras, there are shops in Delhi that make CDs of the negatives that you give for developing. Once you have them in an electronic format, you can do the rest!