Petri's late M42 mechanical SLR — the MF-1, metered manual, 1977.
The Petri MF-1 was a 35mm film SLR made from 1977 and was among the last cameras associated with the Petri name. Like the FTX it used the M42 screw mount rather than the older Petri bayonet, and it came at the very end of the brand's independent life as a simple, budget body.
It is a single-lens-reflex camera for 35mm film on the M42 screw mount. The MF-1 used TTL metering and a mechanically controlled focal-plane shutter, operated in metered manual, so it can fire without a battery, the cell powering only the meter. It accepts the broad range of universal M42 lenses.
It suits beginners and students who want a low-cost mechanical body that takes common screw-mount lenses. The battery-independent shutter and simple controls make it forgiving to learn on, while the M42 mount keeps lenses cheap and available.
On the used market the MF-1 is uncommon but benefits from the wide M42 lens supply. Check the foam seals and mirror-damper foam, confirm the mechanical shutter fires at all speeds without a battery, and test the meter with an appropriate cell. Inspect advance, rewind and screen; the Petri build is basic, so watch for wear, though the M42 lens pool eases ownership.