Some "first" facts about Pentax (founded in 1919)...
1. First Japanese Single Lens Reflex camera (camera: Asahiflex I, 1952)
2. First production camera with instant return mirror (camera: AsahiFlex IIB, 1954)
3. First TTL (through the lens) metering system (camera: P, 1964)
4. First 35mm SLR using aperture priority auto exposure (camera: ES, 1971)
5. First 35mm SLR using a pentaprism (camera: Asahi Pentax AP, 1957)
6. First 35mm SLR with a built-in flash
7. First auto-focus 35mm SLR camera (camera: ME-F, 1981)*
8. First lenses with multiple-layer coatings (Super Multi Coating; 7 layers)
9. First point and shoot camera with a zoom lens (camera: IQZoom 70, 1986)
10. First weather-resistant zoom point and shoot (camera: IQZoom 90WR, 1991)
11. First SLR to automatically select proper program (camera: ZX-10, 1996)
12. First medium format SLR with auto-focus (camera: 645N, 1997)
* You may have noticed #7 above. Well, there has been some confusion on the web recently about the start of auto-focus cameras. Some people think the first one was Minolta, while some think it was Canon. It actually depends on what type of auto-focus camera you are referring to. Originally, Leica patented the first auto-focus technologies, but didn't actually mass produce an AF camera until much, much later. The first mass-produced AF camera was a point and shoot, a Konica C35 AF, released in 1977. The first SLR AF was the Polaroid SX-70 OneStep. The first 35mm SLR was the Pentax ME-F (it used a motorized lens on a camera body that included focus sensors). Nikon then released their first AF camera (F3AF) a few years later. In 1985, Minolta released a new AF system, which was the first SLR to have integrated auto-focusing (the AF sensors and drive motor were housed in the camera body). Minolta's first AF camera was the Maxxum 7000. The same year, Canon also released their own AF system. This system housed the AF motor in the lenses instead of the body. The first AF camera for Canon was the T80 (this camera was only made for one year and the compatible lenses had it's own AC mount designation which is not compatible with the EOS system).