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The 1950's Gossen Bisix photographic exposure meter is a wonderful example of engineering design. Small, very lightweight and functional. Manufactured in West Germany, the meter requires no batteries, as it uses a selenium photovoltaic cell to produce a current from incident light. The current flows into a sensitive moving coil ammeter, the needle of which moves over a scale graduated 1 to 10.
The selenium cell has an ingenious corrugated transluscent screen, which can be moved using a side mounted slide to cover the cell. When uncovered, reflected light is measured. When the diffuser blind is used, incident light is measured.
These days, we take for granted the computing power of silicon integrated circuits to perform calculations. The Gossen Bisix however, designed long before ICs were invented, uses a purely mechanical computer! Beautifully simple, two moving parts, no batteries, nothing to go wrong! In order to determine shutter speed, the film speed is "dialled in" using the top ASA/DIN tab. Then the reading from the meter is dialled in by rotating the computation disc at the left hand side. On the right hand side, you choose your aperture on the fixed scale and, alongside on the computation disc, is the shutter speed! Simplicity itself.
This particular meter has a serial number 012696, indicating that it is quite an early example - the type 1 being serialised 0 - 50000, before being superseded by the Gossen Bisix 2. It's in perfect working order, as can be seen in the following video, not bad for something I believe was designed in 1953. It's robust!
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A STEAMPUNK NOVEL, FULL OF
ANARCHIC EXPERIMENTAL SCIENCE
"Hodges emitted a scream the like of which
I hadn't heard since his scrotum was burned off
Unrelated to this post, below is an example of
eclectic science esoterica
Snowflake 300um LTSEM
Rime frost on both ends of a "capped column" snowflake
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