
Olympus OM system

The Olympus OM System was a line of 35mm single-lens reflex cameras, lenses and accessories sold by Olympus between 1972 and 2002. The system was introduced by Olympus in 1972. The range was designed by Yoshihisa Maitani, chief designer for Olympus, and his staff; "OM" stands for "Olympus Maitani".
The nucleus of the system was a series of compact bodies divided into an advanced series and a later consumer-oriented series. The first model was the all-mechanical M-1 which, after pressure from Leica (which already had an M1 model), was renamed OM-1. At the same time the M system was renamed OM System. The camera included a full-aperture TTL Cadmium-sulphide (CdS) exposure meter, and a bayonet lens mount of relatively large diameter. By the end of the 1970s it was joined by the semi-automatic OM-2 and consumer-oriented OM-10. Olympus continued the naming pattern with the 'professional' OM-3 and OM-4, and the consumer-level OM-20, OM-30 and OM-40. The cameras were accompanied by a series of Zuiko-branded lenses, as well as a generous selection of accessories. The majority of OM bodies and lenses were manual-focus only; the OM-707 of 1986 was the only true autofocus model.
Camera models.
Olympus produced a wide variety of OM camera models over the years. These were divided into two distinct series. Cameras with single-digit model numbers were the 'professional' series, optimized for more advanced features and durability. Two-digit (or more) model numbers, or letters, meant a 'consumer' camera designed for ease of use.
All the consumer-grade models were discontinued after 1992, since the market for manual-focus SLR cameras had declined greatly. The consumer line returned in 1997 with the Cosina-sourced OM-2000 model. Professional and advanced-amateur demand for the high-end models continued, and they were produced until 2002, along with the consumer-grade OM-2000.
Professional cameras.
OM-1.
The Olympus OM-1 was a manually-operated 35 mm single-lens reflex camera forming the basis of the OM system in 1972. At first called the Olympus M-1, Leica disputed this designation and it was changed to OM-1. It was designed by a team led by Yoshihisa Maitani with a through-the-lens exposure meter controlling a needle visible in the viewfinder. It was noted for its reduction of size, weight and noise. One feature unique to the OM-1, compared to the rest of the OM system, was its mirror lock-up facility which made it ideal for astrophotography and macrophotography.
OM-2.
Introduced in 1975, the Olympus OM-2 was a semi-automatic, aperture-priority camera featuring an electronically controlled shutter. It was based on the OM-1 body, and retained compatibility with OM-1 accessories and lenses. It boasted automatic through-the-lens (TTL) off-the-film (OTF) metering, and exposure was considered very accurate. This was calculated by the measured light reflected off the surface of the shutter, and/or the film surface during the actual exposure. The camera also offered a manual-exposure mode, as in the OM-1. It also introduced the integration of electronic flash into the exposure system using the TTL exposure system.
OM-3.
The OM-3 was an updated version of the OM-1, a manual camera without automatic exposure modes, and an entirely mechanical shutter. It featured a multi-spot metering system (shared with the OM-4) in addition to the centre-weighted metering of the earlier body. It also featured an LCD similar to the OM-4 which could be illuminated in low light. Its main advantage over the OM-4 was its ability to operate without batteries due to its mechanical design. Batteries were only needed for the exposure meter and LCD. It lacked a self-timer and mirror lock-up functions, however.
In 1995, nine years after the OM-3 was discontinued, the OM-3Ti was released. It shared the improvements over the OM-3 that the OM-4Ti held over the OM-4.
