The Olympus OM system was late to the game, but ended up changing the rules of SLR design entirely. Introduced in 1972, this system turned the idea of big, heavy, metal 35mm SLRs on its head by being compact without sacrificing the build or image quality that made SLRs popular.
Yoshihisa Maitani, designer of the Olympus PEN and XA, also led the design team for the OM-1. It and the other single-digit OM series SLRs are very highly regarded. The consumer-grade two-digit models, like the OM-10, are less well-built but come at a lower price point.
Olympus lenses hold their value quite well because the company never skimped on build quality. Instead of having a cheaper lens line like Nikon’s Series E or introducing plastic to their lens construction like Canon, Olympus stuck with solid, metal designs and excellent coatings.
Olympus produced and sold OM series SLRs until 2002, and continues to innovate with small cameras to this day in their Micro 4/3 mirrorless cameras. OM lenses are easily adaptable to these M4/3 cameras as well as other systems, like Canon EF and Sony E.