Digital Cameras

There's a lot of different digital cameras on the market. Read on to determine the features and functions you need.


How digital cameras work

A digital camera is based on similar photographic processes as those used in film photography, so it's worth pointing out how a film camera works first, in order to understand how a digital camera works.

A film camera is basically a light-tight box with a lens at the front, featuring light-sensitive material (the film) inside. The lens focuses light onto the film, while a shutter sitting behind the lens controls the level of light allowed through to the film. A film camera has mechanisms that then allow the film to be wound along, and provide control over the lens aperture and shutter speed.

The other complicated element which then comes into play is the viewfinder. Less expensive film cameras can sometimes have a separate lens that shows in the viewfinder the approximate scene that will be recorded onto the film. A high-quality film camera, known as an SLR (single lens reflex), instead uses the camera's main lens for the viewfinder. The advantage of this is that what the user sees via the viewfinder is exactly what will appear on the film - even down to seeing the focus of the picture.

Although digital cameras work on a similar principle, the biggest difference between them and their predecessors is the replacement of film with light-sensitive sensors. Here, the light sensor device absorbs the light particles and converts them into electrical charges. Sensors can be thought of as a grid of thousands or millions of solar cells which transform the image into an electrical charge. The bigger the hit of light to the sensors, the greater the electrical charge produced, which means the photo will be more exposed.

Once these charges have been recorded, the next step is to read the accumulated charge of each. When capturing and converting these charges, the sensor cells are colour-blind, recognising only the intensity of the light. Digital cameras, therefore, have to employ coloured filters to produce the spectrum of colours which is present in the picture. The standard way of doing this is to rotate coloured filters across the sensor. These are usually green-red and green-blue filters.

Once both the charge and colour have been recorded, the final step is to convert the analog signal to a digital one by passing the information on the sensor through an analog to digital converter. This will turn the information into binary form, which can then be interpreted by a PC.

The predominant sensor used in digital cameras today is a Charge Coupled Device (CCD), although Complementary Metal Oxide Semiconductor (CMOS) sensors are occasionally still implemented. Generally a larger sensor will produce a better quality image, as it is able to capture more light, which is one of the chief reasons why SLRs offer superior image quality to their smaller compact brethren. That said, the size of the sensor is less important than the number of pixels it has. This is measured in megapixels, or millions of pixels, and most cameras these days start with at least a 5Mp sensor.

However, the CCD isn't everything, either: some of the higher-end cameras have only 5Mpr 6Mp sensors, and rely on a more expensive lens. Another thing to note is that most sensors in digital cameras are smaller than their film counterpart, so the lens required to produce similar-sized images via a digital camera is smaller. So, while the lens on a digital camera doesn't need to be as big, it will nevertheless affect the quality of your image as much as a lens on a conventional camera.

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Struggling for Christmas presents this year? Check out our Christmas Gift Guide for some top tech suggestions and more.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

GoodGearGuide Staff

Good Gear Guide

Most Popular Reviews

Follow Us

Best Deals on GoodGearGuide

Shopping.com

Latest News Articles

Resources

GGG Evaluation Team

Kathy Cassidy

STYLISTIC Q702

First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni

STYLISTIC Q572

For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell

LIFEBOOK UH574

The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi

STYLISTIC Q702

The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott

STYLISTIC Q702

My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.

Latest Jobs

Shopping.com

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?