07/31/2026
Welcome to another edition of Full Circle’s camera of the week! Today we are proud to showcase the petri half 7.
The Petri Half 7 is a vintage half-frame 35mm film camera released in 1962 by the Kuribayashi Camera Industry (which renamed itself to the Petri camera company that same year). Built to compete with the highly popular Olympus Pen series, the Half 7 offered a unique pocket-sized design and completely battery-free automatic operation.
Chronology and Context
Predecessor: It arrived as an updated, streamlined version of the 1961 Petri Compact E and the original 1960 Petri Half.
The Name: The “7” in its name aligns it with Petri’s full-frame flagship line from the same year, the Petri 7rangefinder.
Launch Price: At release, it retailed in Japan for 8,800 yen (roughly $25 USD at the time).
Film Format: Standard 35mm film, exposing 18 × 24 mm half-frames(Vertical/Portrait orientation by default).
Frame Yield: Doubles standard roll capacities; yields 72 exposures on a 36-exposure roll.
Lens: Petri 28mm f/2.8 coated lens (Tessar-type formula, 4 elements).
Shutter: Petri S programmed leaf shutter.
Shutter Speeds: Bulb (B), and automatic speeds running from 1/15s to 1/250s.
ISO/ASA Range: Supports film speeds from ISO 10 to 200.
Weight
Approximately 440 grams.
Unique Mechanical & Design Facts:
The “Circle-Eye” Meter: The camera utilizes a circular selenium cell array that completely surrounds the front element of the lens. This design ensures that if a filter is screwed onto the lens, the meter automatically compensates for the reduced light.
Zero Batteries Required: The selenium meter generates its own micro-electricity from ambient light to power the exposure system and the viewfinder needle. It is entirely mechanical and completely independent of external batteries.
Novelty Bottom-Winder: Unlike most half-frame cameras that use a thumbwheel on the back, the Half 7 uses a large circular winding k**b located on the bottom-back edge of the body.
