C41
Kodak Portra 400
Kodak Portra 400 is a professional C-41 color negative film known for flexible exposure latitude, natural skin tones, and fine grain.
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The Petri Flex 7 (1963) is a 35mm manual-focus SLR produced by Petri Camera Co., Ltd. of Tokyo. It uses the Petri breech-lock lens mount — a collar-locking bayonet distinct from any other system — paired with a range of CC Auto Petri lenses headed by the capable Petri 55mm f/1.8 normal. The shutter is a horizontal-travel rubberised cloth focal-plane curtain running from 1s to 1/1000s. An uncoupled selenium meter cell is integrated into the body but reads independently of the shutter and aperture settings, requiring the photographer to manually transfer the EV reading to lens and shutter controls.
Reference
Recommended film stocks for the 35mm format your camera takes.
C41
Kodak Portra 400 is a professional C-41 color negative film known for flexible exposure latitude, natural skin tones, and fine grain.
View profile →BW
Kodak Tri-X 400 is a classic black-and-white film known for strong tonality, visible grain, and documentary character.
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Kodak Gold 200 is a daylight-balanced C-41 color negative film with warm color, moderate grain, and a classic consumer-film look.
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Labs in our directory that process 35mm film.
Before you buy used
About this camera
Japan's budget SLR from a company that never quite broke through — the Flex 7 offered solid optics and a unique breech-lock mount to photographers who couldn't afford a Nikon.
| Field | Value |
|---|
| Format | 35mm |
| Mount | Petri breech-lock bayonet |
| Years | 1963–1971 |
| Shutter | 1s – 1/1000s + B, horizontal rubberised cloth |
| Flash sync | X: 1/60s; FP: all speeds |
| Meter | External uncoupled selenium |
| Modes | Manual |
| Viewfinder | Pentaprism, split-prism focusing aid |
| Weight | ~720 g |
Petri Camera Company began as Kuribayashi Camera Industry in 1907, one of Japan's oldest camera manufacturers. Through the postwar period Petri produced rangefinder cameras before pivoting to SLRs in the early 1960s to compete with the growing market led by Nikon and Miranda. The Petri Penta (1959) was the company's first SLR; the Flex 7 (1963) was a substantial refinement. Petri adopted the breech-lock lens mount — already established by Canon's FL/FD breech-lock system — but in their own incompatible implementation, which limited third-party lens support and ultimately kept Petri in the second tier of the Japanese SLR market.
The company continued refining its SLR line through the 1960s and 1970s but never achieved the market share of Nikon, Canon, or Minolta. Petri Camera went bankrupt in 1977.
The Petri Flex 7 is a collector's camera as much as a shooter's camera. It represents the broad Japanese SLR ecosystem of the 1960s — the dozens of manufacturers who competed briefly before the market consolidated around Nikon, Canon, Minolta, and Olympus. The Petri breech-lock mount and CC Auto Petri lenses are entirely self-contained; no cross-compatibility with other systems exists, so the camera and its native lenses form a closed ecosystem.
For photographers, the Flex 7's horizontal cloth shutter is durable, the pentaprism finder is bright, and the CC Auto Petri 55/1.8 produces good results stopped down. Prices are very low because the lens ecosystem is limited — but for a photographer who just wants one body and one lens for deliberate manual shooting, the Flex 7's mechanical quality exceeds its market value.
Petri breech-lock mount. Native CC Auto Petri lenses: 28mm f/3.5, 35mm f/2.8, 55mm f/1.8 (standard), 55mm f/2, 100mm f/3.5, 135mm f/2.8, 200mm f/4. Some third-party lenses (Spiratone, Soligor) were produced in Petri mount in limited quantities. No adaptation from other mounts is practical due to the breech-lock's flange distance. Accessories: Petri dedicated flash units, PC sync cord, close-up extension tubes.
BW
Ilford HP5 Plus is a flexible ISO 400 black-and-white film with classic grain and strong push-processing tolerance.
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Kodak Ektar 100 is a fine-grain C-41 color negative film with saturated color and high sharpness.
View profile →Petri Flex 7
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