The Olympus AF-1 Twin (Infinity Twin in the US) of 1988 has a biaxial (two-lens) system so the user can switch between a 35mm wide-angle lens and a 70mm telephoto lens at the touch of a button. It also has the weatherproof design used on the other models in the Olympus AF series. The AF-1 Twin has moulded plastic lenses, which Olympus used for the first time in this weatherproof series, after the development of technology to overcome moisture absorption and other issues. A Quartzdate model was available.
- Lens: Switchable between 35mm, f/3.6 (3 elements, 3 groups) and 70mm, f/6.3 (5 elements, 5 groups).
- Auto-exposure, with shutter speeds of 1/15-1/750s.
- DX decoding of 35mm film, ISO 50-3200.
- XA-style lens protection.
- Tripod socket.
- Power: 3V Lithium CR123A or DL123A (2x)