Webcam Supertest (Page 2 of 8)
Terminology And Features
These days most technology comes with an often bewildering array of associated jargon and marketing hype which can hinder as much as help, and sadly webcams are no different. Thankfully there are a few key terms worth noting which will aid our comparisons and help you to select the right webcam for your needs.
Terminology
- Pixels: All digital images are made up of small blocks called pixels, similar to the way that a mosaic is constructed. Generally speaking, image quality and detail increase with the number of pixels present in the image.
- Megapixels (MP): As digital images can run into millions of pixels, the abbreviation of megapixels (one million pixels) is often used. For example, an image 640 pixels wide x 480 pixels high = 307,200 pixels = 0.3 megapixels (rounded to the nearest tenth).
- Native Resolution: Often referred to as ‘true’ resolution, this is the optimum number of pixels a webcam can produce when capturing an image. The native resolution of a webcam is usually expressed in terms of megapixels.
- Interpolated Resolution: Sometimes known as ‘digital’ resolution, this is the maximum number of pixels a webcam can produce after software enhancement of the native resolution images. However, as the webcam can only produce its native resolution level of detail, interpolated images are usually of low quality because the software can only take a ‘best guess’ of what an enlarged image would look like. Interpolated resolution is again usually expressed in megapixels.
- Frames Per Second (FPS): Webcams produce video by taking many individual images every second and playing them sequentially to create the illusion of movement, similar to how an animation works. The higher the frames per second, the more fluid and realistic the movement. Often the computational demands of capturing high-resolution images results in a lower number of frames per second than for low-resolution images which are quicker and easier to process.
- USB Video Class: Drivers and software traditionally need to be installed before a webcam can function correctly. USB Video Class is a common standard which allows certified webcams to instantly run on any Windows XP Service Pack 2 (or better) computer without the need for additional software, much like how a USB flash drive works. USB Video Class support will be a requirement for all Windows Vista certified webcams (although older webcams should still be compatible).
- Image Quality: There are many different ways to describe image quality, but for our purposes the following terms may be referred to: saturation (the intensity of a specific hue), exposure (the amount of light captured by a webcam), noise (the amount of unwanted ‘grain’ or interference in an image), artefacts (the amount of ‘blockiness’ and other image corruption introduced after compressing an image to reduce its file size).
(Naturally these explanations are simplified, so if you wish to find out more then just use your favourite search engine to explore the wealth of information available on the internet.)
Features
In addition to the above technical terms, there are a wide variety of features which each company includes in their webcams. Thankfully the vast majority of these features are self-explanatory, for example, automatic face tracking detects your movement and adjusts the image to keep you centred in the picture. Other features include wide-angle lens, which produce a broader image useful for showing two or more people, through to built-in microphones, which save the need to wear a headset or have a separate microphone.
What features are the most important when looking for a webcam? That question really comes down to what you wish to use your webcam for. Certainly native resolution is more important than the interpolated resolution, but as most internet communication software runs at 320x240 pixels or 640x480 pixels, having a high native resolution is not the ‘be all and end all’.
One other feature worth noting is the choice of mount which a webcam uses. Some webcams are specifically designed for notebook computers and will not usually work with desktop monitors (without the aid of adhesive!). Equally some webcams are large and heavy and are impractical to carry around. Thankfully an increasing number of webcams are adopting a ‘universal’ mount approach, which work with all devices and thus provide the maximum amount of freedom.
Finally, the software features included with a webcam may also play a major role in your purchasing decision. Although virtually all modern webcams support a range of services, such as Windows Live Messenger and Skype, the bundled software goes beyond this and acts as your means of directly interacting with your webcam. For example, the software allows for fine-tuning the picture quality, and may also permit automatic face tracking, special image effects, and a range of other useful features which can enhance your experience.
Having explored the relevant terminology and features, we can now begin our comparison of the five webcams featured in our supertest.
« Read the previous page, ‘Introduction’.
» Read the next page, ‘Specifications Comparison’.