The Photon is a tiny, straightforward light meter developed by a team of designers. Compared to conventional light meters, which can cost hundreds of dollars, the Photon is constructed around a Raspberry Pi Pico, a microprocessor from the Raspberry Pi company. As a result, it can give a light meter at a substantially lower cost. The price for the Pico itself is only $4. The Photon is a palm-sized light meter made by VEEB, a group of Swiss photographers who moved to make “useful” objects during the COVID-19 pandemic.

According to VEEB, light meters can range from $100 to as much as $1,000, depending on the manufacturer and the offered capabilities. In contrast, VEEB constructed the Photon using reasonably inexpensive components and combined it with basic math and the “code we wrote.”

The entire cost of the parts list is less than $50.

The project’s aim, recently highlighted by Raspberry Pi, was to give film camera fans a more accessible means of guaranteeing high-quality pictures, particularly if their cameras lack built-in light meters. VEEB wants to utilize them specifically with two cameras that don’t have light meters: the Hasselblad 503CX and the Pentax Asahi.

The idea behind light meters is rather straightforward. After being given a target aperture or shutter speed by a photographer, the gadget will read the light in the area to take a photograph that is appropriately exposed and supply the required additional settings.

According to VEEB on the project’s Github, “Photon replicates some of the functionality of more expensive equipment, utilizing a few inexpensive/available parts.” It now measures the intensity of ambient light as well as the red, green, and blue light spectrums, which could enable White Balance readings in later generations.

VEEB shows this in the project video, which shows that when they set a shutter speed, the Pico analyzes the light in the space and gives the appropriate aperture to produce the desired exposure. Additionally, the ISO can be changed, directly affecting the suggested shutter speed.

The VEEB team compared their work to a Sekonic light meter and discovered that the results were identical.
On Github, you can get the whole set of building instructions for the Photon.