Science photographer Ted Kinsman wrote this piece on building and calibrating a photodiode-based light meter:
Being in the professional science photography business, I often get asked to photograph the strangest stuff using some very weird lens combinations. Lately, I was asked to take some motion pictures of "microscopic animals". So I set up the microscope and attached it to a 35-mm motion picture camera – but how do you measure the exposure?
A typical answer would be to use a standard film plane meter, but such a device would not fit my situation, and I would still have to perform a calibration on the device.
The answer to my problem was to simply build the type of meter I needed and then calibrate the device…
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