The vintage Norwood Director Exposure Meter Model S is an analog incident light meter known for its use of a patented hemispherical "Photosphere" sensor and durable, battery-free selenium cell operation. It was manufactured by Sekonic Electric Co. in Tokyo, Japan, after Sekonic acquired the rights from American Bolex.
Key Features and Operation:
Incident Light Metering: The primary method involves placing the meter at the subject's position, pointing the Photosphere (hemispherical diffuser) toward the camera lens to measure the light falling on the subject. This method ensures consistent exposure regardless of the background's brightness.
Selenium Cell: The meter is powered by a selenium cell and does not require batteries.
Pivoting Head: The sensor section can swivel, allowing the user to read the meter at a convenient angle while keeping the sensor aimed correctly.
Exposure Calculation: The user sets the film's ASA/ISO speed on a dial and takes a light reading. The dial is then rotated to match the meter's reading (e.g., in footcandles), presenting a range of corresponding shutter speed and aperture combinations for correct exposure.
Accessories: It typically includes a range-multiplying slide (a perforated plate that fits over the sensor) for measuring very bright light conditions, extending the range up to 32,000 footcandles.
