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Press release no 3 24062003


Amsterdam, 24 June 2003 – The Four Thirds System (4/3 System) has been introduced as a new standard for next-generation digital SLR camera systems that ensures interchangeable lens mount compatibility. Olympus Optical Co., Ltd. of Japan and Eastman Kodak Company of the United States had resolved to aggressively implement this new standard in their respective product lines, and to establish the Universal Digital Interchangeable Lens System Forum, an industry forum that will promote acceptance of the Four Thirds System by other camera manufacturers. Fuji Photo Film Co., Ltd. has already agreed to participate in the new standard.

System Overview

The Four Thirds System is not based on existing standards for 35 mm film SLR camera system lenses, but instead establishes a new common standard for the interchange of lenses developed exclusively to meet the optical design requirements of digital SLR cameras.
4/3-type Image Sensor Size

The Four Thirds System uses a 4/3-type image sensor and facilitates the development of dedicated digital camera lens systems that maximise image sensor performance and ensure outstanding image quality while also being smaller than 35 mm film SLR camera lens systems.

Lens Mount Standardisation

By establishing an open standard for camera body lens mounts, the new system will make it possible to standardise lens mounting systems, something that has been impossible to achieve with digital SLR cameras that are based on existing 35 mm film SLR lens systems. At the same time, the new system standard will set a rule for both the image circle size (the diameter of the area in which the subject is resolved) and the back focus distance (the distance from the lens mount to the image sensor).

Development Background of the New Standard
Current digital SLR cameras with interchangeable lenses are essentially based on conventional 35 mm camera systems. As a result, they must be equipped with image sensors that are comparable in size to 35 mm and APS film. However, because the imaging characteristics of these large CCDs are fundamentally different from those of film, a number of issues can prevent them from achieving their full performance potential. These include: (1) Although film is capable of responding to light striking the surface at a high angle of incidence, a high angle of incidence can prevent sufficient light from reaching sensor elements at the periphery of a CCD and result in reduced colour definition, particularly when shooting with wide-angle lenses. (2) To achieve the resolutions required by the micron pitch of today's CCDs, the demands of optical design tend to result in the use of larger and heavier lenses.

Moreover, manufacturers of digital SLR camera systems have until now adopted the mounting systems used in their own respective 35 mm film SLR cameras, making bodies and lenses produced by different manufacturers incompatible with one another.

In light of these circumstances, the new Four Thirds System standard was conceived to facilitate the design and development of digital SLR cameras and lenses that maximise the performance potential of digital imaging sensors, and provide users with product advantages such as compact size, handling ease, and enhanced functionality.


The major benefit of the Four Thirds System is that it allows the design of dedicated, high-performance digital camera lens systems that are more compact than 35 mm film SLR camera lens systems. The impact of the more compact lens size will be especially marked on telephoto lenses, making it possible to produce.