From the Store description:
Smart Lights (support only 8.1) is a handy tool for measuring the power of Light (Lux) value by using device light sensor. It detects the Light Intensity for the different workstations like Hospitals , Offices, Residences, Hotels, Educational institutions and Concert Halls etc. Then the results will suggest you to decide to participate in activities in accordance with the light intensity was measured. Such as bedtime, reading, walking, ...
With full content and high science, the app will help you to use your smartphone in creative ways:
- Measure the quality of sleep through the bedroom light, so that you improve your health
- Measure the intensity of sunlight to help you protect your skin
- Measure the light intensity around your work environment
It works really well and is responsive, changing readings around once a second (the ambient light sensor on most phones is on the front, near the earpiece, by the way). Here's a brief walkthrough:
It's amazing how much the human eye compensates for low light conditions, but a light meter, here on the phone, will always tell the truth. And, with my photo-geek hat on, knowing how bright the light is could well help me work out the best way to shoot a particular scene...