The Rolleiflex SL66 is a single lens reflex camera made by Rollei, in regular production from 1966-82. The SL66 represented a change in direction for Rollei, which until that time had focused almost exclusively on its popular twin lens reflex cameras, the Rolleiflex and Rolleicord.
Rolleiflex SL66 Wikipedia
In 1957, an agreement between Reinhold Heidecke, inventor of the Rolleiflex TLR, and Victor Hasselblad, inventor of the Hasselblad SLR, was reached to ensure that Rollei would not manufacture SLR cameras, and Hasselblad would not manufacture TLR cameras. However, the rapid adoption of SLRs during the 1960s meant that Rollei risked falling behind in this market, at the same time that demand for its TLRs was decreasing. In 1964 plans were made to create a new, technologically advanced SLR to be introduced at the 1966 photokina festival.
Like the Rolleiflex TLR and the Hasselblad SLR, the SL66 uses 120 or 220 film to produce frames of 6×6 cm. It also incorporates several features that are unique or noteworthy in an SLR camera:Reverse-mounting lenses. Most SL66 lenses (with the exception of the very wide or very long lenses) could be reversed and mounted to the camera without adapters, for use in close-up macro photography.
Lens bellows to accommodate focusing when the lenses are reverse-mounted. Again, this is impossible for most SLR cameras without special adapters.
Lens tilt movement. The lenses could be tilted up to 8 degrees either up or down, to take advantage of the Scheimpflug principle, enabling greater depth of field, especially in close-up photographs.
The SL66 uses a focal-plane shutter, although several lenses were available in leaf shutters to enable much higher flash synchronization speeds.
Several later cameras based on the SL66 were made, including the SL66E, SL66X, and SL66SE. The most prominent changes in these newer models involved increased use of electronics in metering and flash synchronization. The SL66SE remained in production until 1992.