Digital Cameras

The Four Thirds System

Originally developed by Olympus, and since 2005 jointly developed by both Olympus and Panasonic, the Four Thirds system is an innovative new design and development standard for Digital SLR cameras.

The aims of the Four Thirds system are:
1. To bring the development of Digital SLRs in to the digital age;
2. To promote better camera mobility by allowing for more compact SLR cameras;
3. To be an open standard so as to ensure both expandability and compatibility of products made by different manufacturers.

35mm film cameras were originally developed in the early 20th century to take advantage of the 35mm film already used to make movies. They quickly became the standard camera type around the world. Even now that most cameras no longer use film and have become completely digital, they basically still conform to the same standards designed for 35mm film. In designing the Four Thirds system, the aim was to develop a new standard specific for digital photography which enabled the very best digital picture quality and camera portability -- without being bound by conventions set half a century ago when 35mm film was the only choice.

It is the image sensor (or CCD) within a modern digital camera which corresponds to the physical film in a traditional camera. Accordingly it is the size of this sensor which basically determines the total size of the camera as both the body and lens must be optimised to house and work with the size of the sensor. Research determined that the ideal sensor size in the digital age to provide the optimum balance between digital image quality and lens size was 4/3rds that of 35mm film - thus giving the standard its name. By reducing the size of the sensor much more compact digital SLRs can be constructed without compromising the quality of captured images.

One of the most important parts of this standard is that Four Thirds lenses are newly designed for the unique requirements of digital image sensors (CCDs) rather than for 35mm film -- unlike lenses available for other 35mm equivalent digital SLR standards. Why is this important? Well, unlike film, for the best results, the light needs to strike the sensor at an almost perpendicular angle or colours can be misrepresented and the corner of images can become shaded. Four Thirds lenses are designed from the bottom-up to work with digital sensors and thus ensure brilliant digital photos.

Finally, the Four Thirds System provides and open standard for the diameter of the lens mount, the size of the image circle, the flange-focal distance, and more. Thus with cameras and lenses available from many different companies, users will be uniquely able to interchange Four Thirds lenses and bodies from different manufacturers giving a much wider amount of choice than was previously available!