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Welcome to the Four Thirds User wiki.

This part of the Four Thirds User website is accessed via the 'KNOWLEDGE' button on the site nav bar near the top of the page.
By using the navigation box on the left you can access the main subsections of the wiki at anytime.

[edit] What is a wiki?

For those who aren't aware, a wiki is a piece of software usually used to create collaborative websites. The most famous is of course Wikipedia (wikis pre-date Wikipedia by some 6 years, but due to its popularity its name has become synonymous with wikis).
Many wikis allow anyone to create and edit pages and their content. They are the culmination of the site's users' knowledge on the subjects covered. For example, this site has been created through submissions from the members of the fourthirds-user.com and e-group.uk.net forums. If you want to help improve this wiki, click on Contribute in the navigation box on the left.

[edit] What is Four Thirds?

"Four Thirds" is a standard set up by Olympus and Kodak that aims to create a manufacturer agnostic DSLR platform. The Four Thirds camera system is the only digital stills camera system featuring interchangeable lenses that is not based on system standards from the film era. It specifies key aspects of the design of camera bodies and lenses including the lens mount, aspect ratio (4:3) of the sensor and the image circle projected on to the sensor by the lens. In addition, the cameras released to date, under the Panasonic, Leica and Olympus brands, have also had sensors that are the same size as those used in 4/3" diameter video camera tube. This has led to confusion over the naming of the standard.

The most often touted advantages of the standard are a smaller lens size and near telecentric lenses:
The lenses can be smaller as the size of the imager is approximately 50% of a 35mm frame. This creates a focal length crop factor; the practical upshot of which is that a lens of a given focal length has a field of view half that compared to if it was mounted on a 35mm film (or digital sensor) camera. This means that a 150mm 4/3rds lens gives the view of a 300mm lens on a 35mm film camera. This has obvious benefits for sports and nature photographers.
Telecentric lenses are those that project the light in a straight path directly towards the imager. The combination of high quality lenses and projecting an image circle bigger than the sensor allows the light that reaches it to be almost all following a direct path. This means that conformant lenses exhibit less corner shading (vignetting) than is usual.

Currently there are 7 manufacturers who have signed on to the standard, but the most active and visible are: Olympus Corporation, Panasonic (Matsushita Electric Industrial Co.), Sigma Corporation, and Leica Camera AG:
The complete list includes:

• Fuji
• Kodak
• Leica Camera AG
• Olympus
• Panasonic (Matsushita Electric Industrial Co.)
• Sanyo
• Sigma

Sanyo is a major OEM manufacturer of digital cameras, once reportedly to be the biggest digital stills camera manufacturer, by volume, in the world, However no obvious practical contribution has been revealed from Fujifilm. Kodak, until 2007, was the main supplier of image sensors for Four Thirds cameras. That role has now been taken over by Panasonic.

The official website of Four Thirds is available here.