Asahi Optical (Pentax) Asahiflex IIB1955

History

Asahi Optical began making cameras with the Asahiflex I around 1952 - one of the first Japanese 35mm SLRs. The line progressed through the Asahiflex IA, IIA (which introduced a quick-return mirror so the viewfinder darkening was reduced), and then the IIB, which adopted M42. The IIB represents the moment Asahi committed to a mount standard rather than a proprietary one - a strategic choice that made Asahi lenses compatible with a wide range of bodies from multiple manufacturers over the following decades.

The Asahiflex line ended as Asahi moved to pentaprism designs, first the Asahi Pentax AP (1957) and then the K series, but M42 stayed as the mount family through the entire Spotmatic era (1964-1977) before Pentax switched to the bayonet K mount.

Why It Matters

The Asahiflex IIB sits at a genealogical crossroads: it is simultaneously a late-generation example of the pure waist-level-finder SLR and an early adopter of the lens mount that would define Japanese amateur photography for two decades. M42 became the most widely supported 35mm SLR mount of the 1960s and early 1970s, used by Pentax, Zeiss-Ikon, Carl Zeiss Jena (DDR), Praktica, Zenit, Yashica, Chinon, and dozens of others.

For collectors, the IIB occupies the gap between the very primitive Asahiflex I and the refined Spotmatic era. It demonstrates that Japanese manufacturers were not merely copying German designs by the mid-1950s but actively participating in the establishment of industry-wide technical standards.

Lenses & Accessories

The M42 mount means an enormous range of glass is compatible, though the IIB predates automatic-aperture (auto-diaphragm) coupling, so lenses must be stopped down to the shooting aperture manually before exposing.

Notable compatible glass from the era:

• SMC Takumar (later production, may require stop-down metering adaptation)
• Super Takumar 50/1.4 and 55/1.8 (later, but M42 compatible)
• Carl Zeiss Jena Tessar and Biotar lenses (M42 version)
• Early Industar and Jupiter lenses from Soviet production

No dedicated accessories documented for the IIB beyond standard Asahiflex flash sync accessories.

Sample Photographers / Notable Use

• Used by working photographers in Japan in the mid-1950s before the pentaprism SLR era, primarily for press and industrial work
• Covered in depth in Ivor Matanle's "Collecting and Using Classic SLRs" (Thames and Hudson) as an early Japanese SLR milestone
• Documented in Pentax historical literature as the transitional M42 adoption model

References

• Camera-Wiki: Asahiflex IIB
• Wikipedia: Asahi Optical history - corporate history including Asahiflex line