PETRI PENTA

Name: Petri Penta
Brand: Petri

The Petri Penta came out in 1959. It was the first single-lens reflex (SLR) camera from Kuribayashi Shashin Kōgyō, later known as Petri Camera Company, and it put the company into the competitive 35mm SLR market. It was an ambitious design for its time, with an instant-return mirror system and one of the earliest uses of the M42 screw lens mount.

Overview

Japanese makers were innovating fast in this period, and they were trying to take on German dominance in SLRs. The Penta was released between 1959 and 1962. It was a big departure from Petri's earlier compact rangefinder and viewfinder cameras. Petri positioned it as a high-end amateur and semi-professional tool, with advanced mechanical features and a wide range of interchangeable lenses through the newly standardized M42 mount. It had a vertically traveling focal-plane shutter and an instant-return mirror, which was rare at the time. The viewfinder stayed usable after exposure. Contemporary SLRs kept it dark until the film was advanced, so this was a real improvement.

The Penta had complex mechanics and limited production volume, and that contributed to its fairly short production run. The simplified Petri Penta S replaced it, and later models dropped the instant-return mechanism. Within Petri's lineup, the Penta was the technological flagship. It showed what the company could engineer, even though it was not a widespread commercial success. It also reflected a broader trend among Japanese makers in the late 1950s and early 1960s to experiment with automation and an easier user experience.

Specifications

Specification	Value
Type	35mm Single-Lens Reflex (SLR)
Film Format	35mm (135 cartridge)
Years Produced	1959–1962
Lens Mount	M42 × 1 screw mount (Praktica thread)
Shutter	Cloth focal-plane shutter, speeds 1 sec to 1/1000 sec + B
Metering	None (uncoupled; later accessories allowed external meter use)
Exposure Modes	Manual only
Viewfinder	Eye-level pentaprism with split-image rangefinder spot (interchangeable focusing screens available)
Dimensions	Approx. 148 × 95 × 55 mm; weight approx. 710 g (body only)

Key Features

Instant-return mirror mechanism: One of the first Japanese SLRs to feature automatic mirror return after exposure, enabling uninterrupted viewing—predating similar systems in Nikkormat and Canon cameras.
M42 screw mount: Adopted the emerging universal thread standard, allowing compatibility with a broad range of lenses from Zeiss, Meyer, Pentacon, and later Japanese makers.
High-speed shutter: Offered 1/1000 sec—the fastest available on any production SLR at its launch—achieving this via a vertically traveling cloth shutter.
Interchangeable focusing screens: Allowed users to swap screens for different shooting needs, such as microprism or grid patterns.
Crank-type film advance: A large, rapid-wind lever with a 180-degree throw, enabling faster frame-to-frame operation than many contemporaries.

Historical Context

The Penta launched while 35mm photography was changing. In the late 1950s, SLRs were moving from niche technical tools to mainstream photographic instruments. Demand for through-the-lens composition and easier macro and telephoto work drove that shift. Asahi (Pentax), Nikon and Topcon were refining their SLR designs, while European brands such as Zeiss Ikon and Ihagee (Exakta) held strong reputations. The Penta arrived with several advanced features. The most notable was its instant-return mirror, which was not widely adopted until the mid-1960s.

The competition was stiff. The Asahi Pentax AP series, introduced earlier, had already made M42 a viable standard. Nikon's F-mount system (1959) offered better build and system expandability. The Penta's complex mirror mechanism proved fragile and expensive to produce, which limited its appeal to a niche audience. It was never widely exported, and distribution stayed concentrated in Japan and select European markets. Reviews at the time praised its optical quality and advanced mechanics, but noted reliability concerns and high cost relative to rivals.

Collectibility & Value

Today the Petri Penta is rare and sought after by collectors, particularly those interested in early Japanese SLR development. Fewer than 10,000 units are estimated to have been produced. Working examples are uncommon because the mirror mechanism is complex and the rubber shutter components degrade over time. In good cosmetic and functional condition, the Penta typically sells for $400 - $700 USD at auction or through specialist vintage camera dealers. Fully serviced models command higher prices.

There are several areas to inspect when buying a Penta. The mirror return mechanism must operate smoothly without sticking. The shutter should fire consistently at all speeds, especially 1/1000 sec. The film advance crank should engage without slippage. Common problems are seized mirror springs, disintegrating light seals and fraying shutter curtains. Replacement parts are scarce, so cameras in original, unmodified condition are preferred. Original boxes, manuals, and accessories such as lens hoods or body caps can add significantly to the value.

Similar Cameras

Asahi Pentax Spotmatic (1964) – Shared the M42 mount and refined SLR ergonomics, though introduced later with TTL metering.
Topcon RE Super (1963) – A high-end Japanese SLR with interchangeable viewfinders and advanced optics, but without instant-return mirror.
Praktica FX 2 (1964) – East German M42 SLR with robust build, though slower max shutter (1/500 sec) and non-instant return.
Fujica ST 705 (1962) – Fujifilm’s early M42 SLR, simpler mechanics but more reliable production.
Konica F (1960) – Another Japanese pioneer with high-speed shutter (1/2000 sec) and focal-plane design, though with a non-returning mirror.

Repair & Maintenance

The Petri Penta is fully mechanical and needs no batteries. Light metering has to be done with an external meter or a modern handheld device. The most frequent maintenance problems are in the shutter and mirror mechanisms. The vertically traveling cloth shutter is prone to uneven tension at high speeds, particularly 1/1000 sec, and may need re-timing. If the rubberized cloth has degraded, it may need replacing. The instant-return mirror spring assembly is delicate and often fails from fatigue. Disassembly takes precision tools and familiarity with SLR mirror boxes.

Regular servicing should include cleaning the pentaprism housing, replacing deteriorated light seals around the film chamber, and lubricating the film transport gears. The crank-type advance lever uses a spring-loaded clutch system that can wear over time, leading to incomplete film advance or a risk of double exposure. OEM parts are scarce, so repair technicians often rely on donor cameras or custom fabrication. The Penta is not recommended for novice collectors or for anyone who wants a reliable daily-use vintage SLR.