In 1957, the Asahi Optical Company introduced the Pentax, a 35mm SLR of such instantly classic design it set the pattern for 35mm SLRs for years to come, in both Japan and Europe. The Pentax, along with its later development and likewise classic Pentax Spotmatic would allow Asahi Optical Company to develop into an photographic multinational, eventually leading the company to rename itself after its seminal product and becoming the familiar "Pentax" brand of today. The Asahi Pentax of 1957 featured:

• "Rapid-wind" film advance lever. Prior to the Pentax, 35mm SLRs would have knob winders, with the sole exception of Exakta's left handed lever
• Film rewind crank, likewise a first for 35mm SLRs.
• Instant mirror return - unique to the Pentax and its immediate predecessor, the Asahiflex IIb
• Microprism focusing aids on the focus screen - unique to the Pentax

Moreover, the Pentax placed controls in locations that would become standard on 35mm SLRs from all manufacturers, such as the right-handed rapid wind lever, the bottom right mounted rewind release, and film speed reminder around the film rewind crank, a location that remained standard even when the dial went from being merely a reminder to the photographer to actually controlling the light-meter built into later SLRs.

The two photographic giants of today, Canon & Nikon, would not introduce their own SLR cameras until 1959 with the Canonflex and the legendary F-series respectively.

Perhaps most importantly, the Pentax offered these features at a reasonable price, putting 35mm SLR photography into the hands of an ever greater proportion of the population.

Some measure of the significance of the Pentax may be gained from the fact that the 42mm screw lens mount it featured would, with the help of the later Pentax Spotmatic, become known as Pentax Universal Screw Mount , even though it had been introduced by Contax in 1949. This ushered in a "Golden Age" of lens interoperability, with owners of M42 equipped cameras able to mount lenses from Zeiss, Yashica , Soligor , Vivitar, Topcon , Sigma, Chinon , and many more as well as Asahi's own highly regarded Takumar series of lenses. This was ended by the increasing need for more sophisticated lens-body communication in order to implement shutter priority exposure, program auto exposure, and finally, autofocus.