Every light meter has a sensor to measure the amount and quality of light that is hitting on a surface. If measuring light from a relatively small but strong light source (i.e. a very powerful LED light) the sensor cannot absorb all of the light emitted. You may have noticed that all handheld light meters use a white plastic bulb that covers the sensor. This is called a diffuser. It is nothing more than a thin, almost transparent, plastic cap. Placing a diffuser in front of the sensor will spread the light evenly and allows the sensor to measure more accurately.
Why Your Smartphone Needs a Diffuser
Our grow light meter app Photone (previously named Korona) uses your smartphone's front camera to measure light. The camera is way more elaborate (and more expensive) than the light sensors built into handheld light meters and it allows Photone to measure more accurately then a standard light meter. Nevertheless, the light hitting the camera does not get diffused at all. This is desired for taking a photograph, but not for measuring light intensity accurately.
How to Build Your Own Diffuser When Using Photone
You can easily build a diffuser with a strip of strip of regular, multi-purpose matte white printer paper in 22 lbs / 80 g/m² thickness and place it in front of your camera. This will diffuse the light and thus give you an accurate reading. Our video will show you how: