Mamiya RB67 Professional S (1974–1990)
A 2.69 kg slab of mechanical certainty that made medium format affordable - and made you work for every frame.
Overview
Pick up the Mamiya RB67 Professional S and the first thing you notice is the weight. The bare body is approximately 1,450 grams, and with the standard 127 mm f/3.8 lens and a 120 film back it comes to roughly 2.69 kg. This camera does not whisper. It demands a tripod, and it pays you back with a 6×7 cm negative that is 4.5 times larger than a standard 35mm frame. That negative is the reason portrait and commercial photographers carried this thing up stairs and into studios for decades.
Introduced in 1974 as the second generation of the RB67 system, the Professional S refined the original 1970 design rather than rethinking it. Mamiya kept the fully mechanical internals - no batteries required for shutter, focusing, or film advance - and worked on ergonomics and operational reliability. Film enthusiasts who prize its tactile precision still use it. The RB67 Pro-S ran until 1990, and the broader RB67 lineage continued to 2010 across its model variants.
The "RB" in the name stands for Rotating Back. Rather than tilting the entire body for vertical compositions, you rotate the film back 90 degrees. The lens axis stays steady and the photographer's rhythm stays unbroken. It made Mamiya's modular medium format SLR a favorite among professionals during the film era.
Key Features
The Revolving Back — RB67's Party Trick
Mamiya's rotating back adapter defined the system and gave it its name. A 90-degree rotation switches between horizontal and vertical orientations without altering the film's position relative to the lens. In practice, you compose, focus, and then rotate the back for a portrait orientation. The camera stays put, the composition stays framed, and the photographer's eye never leaves the waist-level finder. It sounds simple. Every other medium format manufacturer wishes they'd thought of it first.
Fully Mechanical Operation — No Batteries, No Excuses
The RB67 Professional S operates entirely without batteries. The mechanical leaf shutter (a Seiko #1) lives in each lens, offering speeds from 1 second to 1/400 second plus T and B modes, with X-sync available at all speeds. There is no battery drain to worry about and no electronic failure mode waiting in a cold studio. The camera can sit in a drawer for a decade and fire perfectly on frame one. The body is rated for operation from -20°C to 50°C, which tells you Mamiya designed this for working photographers, not shelf queens.
Bellows Focusing — Macro Without Accessories
Instead of a helical focus mount, the RB67 uses a bellows focusing mechanism built into the body. It extends up to 46 mm, so the standard lens focuses down to 0.35 meters without any extension tubes. Add the optional tubes and you can reach 1:1 reproduction ratios. Any lens in the Mamiya-Sekor lineup, from the 37 mm f/4.5 fisheye to the 500 mm f/6 APO telephoto, racks through its full focus range on the same mechanism. Every lens gets macro capability as standard equipment.
Modular Film Backs — Format Flexibility
The RB67 Pro-S accepts multiple interchangeable film backs: 120/220 roll film giving 10 or 20 exposures respectively, 70mm film for up to 55 exposures, Polaroid packs for instant proofing, and even digital backs for those who've dragged the system into the 21st century. The 6×7 cm primary format can also be adapted to 6×6 cm and 6×4.5 cm via adapters. For studio shooters, this modularity meant you could shoot a Polaroid test, swap to 120 for the real take, and switch to 220 mid-job without wasting a frame — all while the camera stayed locked down on the tripod.
The Mamiya-Sekor Lens Mount and Optics
Lenses attach via a proprietary breech-lock bayonet mount with a safety lock ring, which prevents the lens from being accidentally released mid-shoot. The Mamiya-Sekor optics are multi-coated across the range for high center-to-edge sharpness and minimal distortion. The standard 127 mm f/3.8 lens (aperture range f/3.8 to f/32) has a 77mm filter thread and weighs 835 grams on its own. It's a big hunk of glass, and it delivers the resolving power that 6×7 demands.
Double-Exposure Prevention and Mirror Lock-Up
The Pro-S introduced double-exposure prevention, a refinement over the original RB67 Professional that saved more than a few ruined frames. The system also includes mirror lock-up to minimize vibration. That matters when you're shooting at 1/15 second on a bellows-focused studio camera and want every last line pair of sharpness from that giant negative.
Historical Context
When the RB67 Professional arrived in 1970, the medium-format landscape belonged to the Swedish Hasselblad V-system - precise, respected, and expensive. The Japanese Pentax 6×7, a direct 6×7 SLR competitor launched in 1969, appealed to action-oriented shooters. Mamiya positioned the RB67 as a more accessible alternative, using Japanese manufacturing efficiencies to deliver professional-grade 6×7 SLR capabilities at a fraction of Hasselblad's price. The original Pro-S sold for approximately $900 USD in 1974. That was hardly pocket change, but it was a bargain next to the Swedish option.
The RB67's design traces directly to Mamiya's earlier work. The company began in the 1940s with folding medium-format cameras like the Mamiya Six, shifted to twin-lens reflex designs in the 1950s and 1960s, and entered the press camera market in 1960 with the Mamiya Press series. Those press cameras' emphasis on modularity and adaptability directly influenced the RB67, which was conceived in the late 1960s to bridge the capabilities of the company's existing press cameras and TLR models. The design goals were clear: a bellows-focusing SLR with a revolving back, offering enhanced versatility for portrait and controlled shooting while keeping the modular approach of prior systems.
The Pro-S was the first significant refinement to the original RB67 Professional, with better operational reliability and ergonomics and the same core mechanical design. It sat between the 1970 original and the 1990 Pro-SD, the final iteration of the RB line. CameraWorth sales data shows the Pro-S is still actively traded, with 33 recorded sales at a median of £420 and a range of £125 - £2,750 as of August 2026.
Collectibility & Market
The RB67 Pro-S is no longer manufactured, yet used copies in good condition are readily available through reputable vintage camera retailers and online marketplaces. Film enthusiasts continue to seek it out for its tactile precision and sturdy build, and it remains popular for studio and field use alike.
Market pricing has a wide spread. Recorded sales range from £125 for a body needing work to £2,750 for a pristine kit, with a median of £420. That makes a complete, functional Pro-S setup one of the most affordable ways into medium format. Mamiya-Sekor optics like the 180mm f/4.5 and the Macro C 140mm f/4.5 appear regularly in listings, and the C127mm and 65mm lenses remain common. Factory service is still available from at least one UK technician offering official RB67 Pro-S maintenance.
Owners describe the Pro-S as "a very reliable 120 medium format film camera that still outputs high quality photos today," and the broader RB67 system keeps its reputation as a professional workhorse. It is not a camera for everyone. The weight and size make freehand use inadvisable, and it is essentially a studio camera for tripod work. For those willing to accept that, the RB67 Professional S delivers image quality that rivals systems costing many times more, in a mechanical design that keeps working decade after decade.
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