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 MX-1 designation refers to the pre-production prototype variant of what Pentax shipped in 1976 as the MX. The MX itself was Pentax's first SLR specifically engineered for minimum body size - the K mount had launched in 1975 on the K1000, KX, and KM, and Asahi Optical's engineers were simultaneously developing a compact mechanical body and a compact aperture-priority body. The MX-1 prototype represented the mechanical branch of that development work before final production specifications were locked.
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.
Develop 35mm film
Labs in our directory that process 35mm film.
Before you buy used
This entry documents a prototype configuration. Production MX bodies are widely available and well-supported; the MX-1 pre-production designation refers to development-phase hardware unlikely to appear on the used market.
For the production MX:
About this camera
The development prototype that became the Pentax MX - Pentax's smallest mechanical SLR.
| Field | Value |
|---|
| Format | 35mm |
| Mount | Pentax K |
| Status | Prototype / pre-production |
| Year | 1976 |
| Shutter | Mechanical vertical metal (assumed) |
| Modes | Manual |
| Battery | None required (mechanical fallback assumed) |
When Pentax introduced the K bayonet mount in 1975, the initial K-series bodies (K1000, KX, KM) were relatively conventional in size. Asahi's engineering team had two concurrent projects under development for the next product cycle: a compact mechanical body and a compact electronic body. These eventually shipped as the MX and ME respectively, both introduced in 1976.
The pre-production MX work produced several prototype configurations as the engineering team resolved the challenge of fitting a full-frame SLR mechanism, a pentaprism viewfinder, and a vertical-travel metal shutter into the smallest possible K-mount body. The production MX measured 131 x 83 x 50mm and weighed approximately 495g - at launch, the smallest and lightest full-frame 35mm SLR in production.
The production MX ran from 1976 to 1985 and became one of the most respected mechanical SLRs of its era.
The MX development program is significant because it established the template for compact mechanical SLR design that other manufacturers followed through the late 1970s and 1980s. The Olympus OM-1 (1972) had introduced the miniaturization concept; the MX-1 prototype work represented Pentax's engineering response to that challenge within the K-mount ecosystem.
The production MX that emerged from this prototype work went on to be used by photographers who valued a mechanical backup body that was genuinely pocketable. Its construction - all-metal, no electronics except the meter - made it the choice for expeditions, press work in hostile environments, and any situation where reliability mattered more than automation.
Pentax K mount. All K-mount lenses from the 1975 launch onward are compatible. The M-series lenses (SMC Pentax-M) were the natural pairing for the MX and its prototype phase - compact, well-coated, and optically refined. The SMC Pentax-M 50mm f/1.4 and 50mm f/2 were designed alongside the MX to maintain the compact system philosophy. Wider K-mount glass (28mm, 35mm M-series) extends the system further.
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 →Pentax MX-1
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