Mamiya RB 67 Pro with 90mm F3.8 lens and 120 filmback. ( all the seals are replaced )

The first camera released was the RB67 Professional in 1970. The system comprise of a camera body, viewfinder, back adapter, film back, and lens. The camera body itself is quite simple and fully mechanical. It does not require any battery power. The shutter button is located on the front bottom right of the camera. It can be locked with a twist of the collar. The shutter is cocked manually by pressing down the large lever on the right hand side of the body. The mirror within the camera and shutter in the lens are cocked at the same time. There are two focusing knobs on each side of the camera body similar to the Mamiya C series TLRs. The focusing screens are also interchangeable. The most common back adapter included in the system is the rotating back. The naming of the camera RB67 stood for Rotating Back 6 × 7.

The RB67 was originally designed to supplement the Mamiya C series 6 × 6 TLR system and the multi-format Mamiya Press rangefinder camera system (6 × 4.5, 6 × 7, 6 × 9, others) but has surpassed them in popularity. Back adapters for using Mamiya Press roll film and instant film backs are also available. Due to its heavy weight (almost 2kg for the body alone) the RB67 is often said to be unsuitable for use hand-held use. This isn’t necessarily true – with a decent neck strap the RB67 can easily be used on the move. The flexibility of the RB67 system made it one of the most popular studio cameras in the 1970s.

It takes lenses with the RB mount which is a bayonet type system with a locking ring. Lenses are equipped with Seiko leaf shutters and focus is set on the camera body using a bellows arrangement with a 46mm extension. The click stops can be at half-stop aperture settings, but the shutter speeds can only be set at full stops. A depth of field preview lever is also built-in to the lens. The lenses typically have shutter speeds of 1 to 1/400 of a sec. and a T mode. The T mode, keeps the lens shutter open until the shutter ring is moved onto the 1 sec mark or when the shutter cocking lever is pressed slightly. Since it’s a leaf shutter based camera, electronic flash sync is available at all speeds. Since the system is synchronized, the camera body and lens must be cocked before attaching or removing the lens. To cock the lens ensure that the pins are in line with the red indicators. A majority of the lenses use a screw on 77mm filter making it much easier to swap filters between lenses.

Mamiya Sekor C  90mm F 3.8  Standard Lens

Focusing: Bellows extension system with rack and pinions.

Maximum extension:  46mm. With focusing knob fixing device.

Shutter and mirror cocking: Single-action (75°) cocking by lever on the side of the body.

Composition: 7 elements in 5 groups

Angle of view: 52°

Filter screw diameter: 77mm

Aperture: Full automatic diaphragm (with depth-of field preview lever). f/3.8 to 32 (with click stops for aperture settings).

Shutter: Seiko #1 shutter 1 to 1/400 second and T (Time) Flash synchronization: X contact

Other features: Mirror-up photography. Bulb (B) feature.

Dimensions  : 94x70mm

Weight : 805 gram.