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Monday, July 13, 2020

Digital Cameras: The Basics
13th December, 1997

Want to know more about digital photography? Thinking about purchasing a digital camera but do not know much about it? Then this series of two articles is for you.

This article introduces the basic of digital camera. It is written from the perspective of someone with absolutely no initial knowledge about digital camera. The next article, written by the co-editor of Macination, Rosalie Marshall, examines the Sanyo VPC-6200 digital camera.

Going Digital

Ever since George Eastman first introduced the Kodak box camera to the public in 1888, the humble camera has become an essential equipment in a family holiday. It is the little black box that captures those precious moments of our life, whether happy, funny, embarrassing, sad or simply memorable.

The principle of photography has remained the same, but the chassis and the mechanics have evolved over the years. It has now moved into its next phase of evolution. Consistent with the trend of our times, the camera has finally gone digital.

Although digital camera has been around for years now, it is only recently that the digital camera has become more common largely because the price at the low end has dropped to a more affordable level. Digital camera is now available for less than $500-the magic mark at which a product is affordable to the mass.

Why Digital

Digital camera is an invaluable and indispensable tool for the professional who uses images to communicate, such as desktop publishing. The ability to digitally manipulate the picture and to have systematic control over the process is a dream came true for such professionals. Both time and cost have been saved. But the usefulness of digital camera is not restricted to this group.

With more and more people setting up their own web page, the ability to capture images and put it onto the web page quickly is a definite benefit. While digital camera is unlikely to replace film based photography any time soon (ie. within the next decade or so), it uses is likely to become more and more widespread.

The main advantages of digital camera include:

The Working of Digital Camera

Similar to a conventional camera, a digital camera captures a picture by recording the light that passes through the lens. In a conventional camera, the picture is recorded onto a light sensitive photographic film. The light passes through the lens and exposes the film. In a digital camera the pictures taken are recorded onto a digital storage media. Instead of hitting the photographic film, the light passes through the lens and hits an electronic component called a charged coupled device (CCD).

A charge-coupled device (CCD) is essentially a light-sensitive material on a silicon chip that electronically detect photons (light particles). The chip contains integrated micro-circuitry that registers, both the intensity and color of, the light that passes through the lens.

CCD are available in different quality. They have different number of pixel. A picture is divided into many small square areas that covered the entire image. These small areas are the pixels. Together these pixels form the picture. Pixel come sin various sizes and shapes. Thus, the more pixel the CCD has the finer the detail that the camera can record. This determines the camera resolution. The higher the resolution, the larger that the picture can be displayed without loss of sharpness.

The light signals collected by the CCD are then converted by a microprocessor into a binary format using either a standard or proprietary graphical format. At the same time, the image may be enhanced digitally and/ or digitally manipulated with build-in special effect. Finally, this information is recorded onto the storage media. The image can than be downloaded onto a PC, displayed on a TV screen, or printed out using some additional hardwares.


Most digital camera on the market has a resolution of at least 640 x 480 pixels. A camera that provides less than this is really inadequate. The slightly more expensive varieties can comfortably handle 1280 x 960 pixels. In other words, these cameras can display 300,000 or 1,200,000 odds pixels on the screen respectively. By comparison, color film contains 20 million pixels. So yes conventional photograph has much higher resolution. However, whether it matters or whether you can tell the difference is another question.

If you are unsatisfied with such resolution, you can always get a digital camera that can satisfy your desire for higher resolution. Then again, are you prepared to spend more than $13,000 on such a camera!


The operation of digital camera is no different to your typical point-and-shoot camera. The process is largely automatic. You point the camera towards the objects via the viewfinder (or LCD screen) and click. You are done.

In fact, most digital camera on the market has the same appearance as typical conventional camera. There is no reason (technically) why they should look the same though. The Apple Quick Take, for example, looks very different and distinctive (as is typically the case with Apple product!)..

Output and Storage

With conventional photography at the end of the day you get a piece of paper with the picture on it. This paper is your only means to view the picture. If you are taking slide you can also see the picture using a projector. Digital camera gives you more output and storage options.

The most common way to see the picture is on your computer. This is done through a cable that link the camera with your computer, or, through an intermediary storage media like a floppy disk or PC card. On the topic of cable, many models come with the necessary cables and some even the softwares necessary for the connection and image manipulation. Sadly, not all brands support the Mac.

Alternatively, the camera may provide video output (PAL &/or NTSC) so you can see the picture on a TV. Video output is usually found on in the more expensive camera. This is a handy feature if you want to store the image on videotape or simply to view it on the TV.

File Storage Format

The information representing the hundreds of thousands of pixels that make up a picutres need to be compressed before storage. Image compression, like file compression on your hard drive, uses some fairly clever algorithms to reduce the amount of space required to store the image.

Notice, unlike file compression where the quality of the compressed file is equivalent to the original version, with image compression, the quality may be different to the original. The more you compressed an image the lower the final quality of the image. Ie. Compression permits you to store more pictures on a given amount of storage space but at the expense of the picture resolution.

A very common graphical compression and storage format that is used is JPEG (Joint Photographic Experts Group). Some use proprietary format as well. For example, the Kodak Digital Science range of camera uses a Kodak-designed algorithm to compress the image. Kodak claimed that this proprietary algorithm allows the camera to store more high-quality images.

For those cameras that uses proprietary format, compatibility with the Mac needs to be watch out for. Most support the Mac. After all Mac is till very popular in the desk top publishing circle.

Storage Media

Digital camera uses a variety of storage media: internal memory, proprietary memory card, Flash EPROM, PCMCIA (Personal Computer Memory Card International Association) memory card, floppy disk (so far only the SONY Digital Mavica uses this media). Some camera uses a combination such as internal memory plus optional PCMCIA memory card.

The internal memory variety is adequate if you are an occasional user or where you have constant access to a computer to allow you to download the picture taken.

If you are after heavy-duty storage then the ability to pop in additional storage would be preferrable. Memory cards are more expensive but they have their advantages. They can have greater capacity. It may also make the camera more durable compared to the floppy disk variety simply because there is no mechanical parts. Although the floppy disk is probably the cheapest option. How much can be stored?

The capacity of digital camera is generally comparable to that of the conventional camera. With digital camera the number of picture that can be taken is a function of: the memory capacity of the storage media, the compression algorithms used and the resolution of the picture. The accompanying table illustrates how this varies between a few brands.

At higher resolution more information needs to be encoded. So more memory is required to record it. Most models permit you to select the resolution, although different brands use different names for the choice available. This makes comparison across the brand difficult.

If you are really into digital camera, and can afford it, you can get storage media with large memory capacity that permits you to take hundreds of pictures. The ability to store a large number of pictures without using multiple storage media is a very useful characteristic of digital camera. No longer would you need to carry roles and roles of films with you on holiday. Your luggage would be smaller and you are happier.

Brand/ Model
Storage Options
Number of pictures (per resolution)

Canon PowerShot 350

2Mb Card

up to 47 (economy);
up to 32 (normal);
up to 11 (fine)

Canon PowerShot 350

15Mb Card

350 (economy);
112 (normal);
82 (fine)

Sony Mavica

3.5Ó (HD) floppy disk

up to 40 (standard); up to 20 (fine)

AGFA ePhoto 307

Internal 2Mb

72 (320 x 240) 36 (640 x 480)

AGFA ePhoto 1280

4Mb removable memory

60 (640 x 480); 24 (1024 x 768); 6 (1280 x 960)

Hewlett Packard PhotoSmart

2 MB Card

32 (normal); 16 (fine); 4 (superfine)

Hewlett Packard PhotoSmart

4 MB Card

64 (normal); 32 (fine); 8 (superfine)

Kodak Digital Science DC25

2 MB internal

29 (standard); 14 (high-resolution)

Kodak Digital Science DC50

1 MB internal flash EPROM

22 (good); 11 (better); 7 (best)


Features and More Features

Like conventional camera there are host of features available among the brands on the market. These include: self-timers, date/ time indicator and stamping function, tripot mounting socket, zooming function, etd. Features that I consider more important are outlined below.

The Look and Feel

As mentioned above, many cameras on the market resemble the conventional camera. Although the style you prefer depends on your personal taste but if my experience with conventional camera is anything to go by, the camera should feel solid, but not too heavy, and sit comfortably in your hand. The presence of sturdy side strap like those found in a camcorder is a definite bonus for the traveller- it allows you to hold onto the camera and take picture with one hand.

LCD Viewer

Some, particularly the more expensive one, have a color LCD screen that functions as a both a viewfinder and image viewer. A LCD screen enables you to shoot exactly what you see on a 2 to 3 inch screen.

It is also very useful for previewing the pictures taken. During a trip it is most exciting to be able to view the pictures taken during the day- no longer do you have to wait until you have returned from holiday to have the file developed. Such camera usually also allows you to erase selected pictures that you donÕt really want. The storage media for digital camera is still not that cheap, except perhaps the floppy disk variety, it is more economical to be able to delete those pictures that you are unhappy with.

The Life Blood: Batteries

As with all electronic gadgets batteries are an essential. What battery does the camera use? How long does it last?

In general, it is best to choose a camera that uses more than one type of batteries (eg. Alkaline (AA), Ni-Cad, Metal-Hydride (Ni-MH), Lithium batteries.) Rechargeable variety is great but there is always a chance that the battery may run out of juice in the middle of the day. Worst still, the charger may fail to work, or you cannot find a power-point. Unlikely maybe, but then things that can happen will happen when you donÕt want it to happen! So the ability to pop in a quick Alkaline AA battery would be most welcomed.

Special effect

Some (those near the $1,500 mark) models even have built in special effect. This could be interesting if you are the creative type. Although the same special effect tricks, and more, can be achieved through photo manipulation grogram like PhotoShop. So such capabilities may be more of a gimmick than of any real use.

Sound Recroding

With some digital camera it is possible to record a short sound clip with the picture. Whether this is of any real use really defies me, although this feature could provide a handy means to annotate the picture taken. But if you are better off with a camcorder, perhaps even a digital one that can also take digital still pictures!

Ease of control

How easy is it to control or access the features of the camera: focus control, flash control, album maintenance and resolution. Nothing is more frustrating than inability to access a particular function that you know the camera can do just when you need that particular function.





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