Petri GX-2

The Petri GX-2 is a single-lens reflex camera. It was produced by Cosina and introduced in the 1980s. It is the predecessor of the Petri GX-3. Cosina offered a functionally identical camera as the Cosina CT-10. Production took place in Japan.

Lens system and focusing

A key feature of the Petri GX-2 is its ability to be used with a variety of different lenses, as it has an interchangeable lens mount. Specifically, the camera uses the widely used Pentax K bayonet, which gave photographers access to a wide range of lenses from different manufacturers and focal lengths, from wide-angle to telephoto lenses. Focusing on this 35mm camera is entirely manual.

There is no integrated autofocus system, so the photographer has to adjust the lens precisely to the subject by hand, which encourages a conscious approach to image composition and is often supported by adjustment aids in the viewfinder such as a split-image indicator or microprism ring.

Exposure System and Control

To determine the correct exposure settings, the Petri GX-2 is equipped with a built-in light meter. This is capable of detecting and adjusting film with ISO sensitivities ranging from 25 to 1600.

Exposure is measured “Through the Lens” (TTL) on this SLR camera, i.e., directly through the attached lens. This ensures high metering accuracy, as the actual incoming light is captured.

The camera typically operates in aperture priority mode: The photographer can freely select the desired aperture on the lens to creatively control the depth of field. The camera’s electronics then automatically determine the appropriate, correct exposure time and set it, enabling fast yet controlled shooting.

Shutter, Flash, and Other Features

For shooting situations that require a particularly long exposure time, such as night or astrophotography, the camera features a Bulb mode (B setting). In this mode, the shutter remains open as long as the shutter button is held down, allowing a variable exposure time that can be precisely controlled by the photographer.

To achieve better illumination even in unfavorable lighting conditions or for creative lighting design, an external flash unit can be connected and synchronized to the camera via the hot shoe connector on the top.

For stable and blur-free shots, especially with longer exposure times or when using telephoto lenses, the Petri GX-2 is equipped with a standard tripod thread on the bottom of the body. Furthermore, it is possible to connect a mechanical cable release to minimize vibration when triggering the shutter.

Physical Properties and Power Supply

According to the manual from that time, the Petri GX-2 measures 13.3 cm wide, 8.5 cm high, and 4.8 cm deep. It weighs 450 grams (without lens and batteries), making it a relatively compact and handy SLR camera for its time. According to the manual, the camera requires two S76 batteries (eBay / Amazon*) to power the light meter and other electronic functions. These button cells, often equivalent to LR44 (eBay / Amazon*) or SR44 types (eBay / Amazon*), provide the necessary power for all camera functions.

Film Use and Recommendations for the Petri GX-2

The question of which film to use with the Petri GX-2 is easy to answer: The camera is designed for exposure with 35mm film. This film format, which produces negatives or slides in the standard format of 24 mm x 36 mm, is still produced by various manufacturers today and is readily available. Developing such films can be easily done in most professional photo labs.

For attractive color images with natural tones and good flexibility, the Kodak Portra 400* has proven itself. However, those seeking classic black-and-white images with fine grain and good tonal reproduction will find the Ilford FP4 Plus* an excellent choice. Both films are known for reliably producing decent images and, according to many reviews and user experiences, are well-suited for everyday photographic use.

The color film is developed using the standardized C-41 process. This chemical process is offered by most professional photo labs worldwide, ensuring straightforward processing. After each exposure, the film must be manually advanced to the next image, typically via a quick-release lever on the top of the camera.

Production of the Petri GX-2 was discontinued long ago. Therefore, interested photographers can now only find it on the used market. The value of a used version of this camera depends primarily on its optical and technical condition, as well as any accessories included. However, it often represents an inexpensive way to get started with analog photography with the versatile K bayonet.