This is How a Match-Needle Exposure Meter From a 1971 Canon Works


Technology Connections, a YouTube channel that covers a big selection of attention-grabbing know-how tales, has shared this 28-minute video that explores how the Canon F1 from 1971 works, with particular element centered on the digicam’s gentle meter.

Along with studying particular particulars in regards to the Canon F1, the host truly goes into a lot of element about each the historical past of phrases like ISO and the way f-stops are calculated, and the way shutter pace and aperture work collectively to create an publicity. If you happen to’re new to pictures and need a pretty quick but thorough clarification of how all of the settings on trendy cameras work, this video is a surprisingly good place to start out.

The primary matter of the video, although, is a know-how referred to as a match-needle publicity meter. It is the one a part of the Canon F1 that requires a battery to function and works in a different way than trendy publicity meters. Match-needle publicity meters, additionally referred to as selenium meters, are based mostly on the photoelectric properties of the ingredient selenium. Based on a detailed breakdown of the know-how here, selenium meters are an instrument “which is linked to the anode and cathode of a selenium photocell that produces roughly electrical energy when uncovered to roughly gentle.”

It’s a fascinating previous digicam know-how that isn’t used a lot at the moment. They didn’t age properly, as selenium cells tended to generate much less present as they had been used through the years and had been uncovered to the weather like gentle, warmth, and moisture. As a outcome, many aged selenium meters should not correct at the moment or are utterly useless. Nonetheless, it’s doable if a selenium meter was by no means used, it might nonetheless operate completely advantageous regardless of its age.

For extra info on match-needle publicity meters, you need to learn this detailed article here, and for extra deep-dives into know-how, you’ll be able to subscribe to Technology Connections on YouTube.

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