IMPORTANT NOTE: You need an 18% grey card to use this app
PocketChris Incident Meter calculates the exposure time from two light measurements taken off a grey card. It works like an incident light meter for your camera. Use a simple 18% grey card, take two spot measurements with your camera and get exposures that rival an expensive incident light meter.
- set your camera to manual mode, choose an appropriate ISO and aperture
- take two spot measurements off the 18% grey card, one with the card facing the brighter side, one with the card facing the darker side
- enter both shutter speed values into the app and set your camera to the closest shutter speed suggested by the app
Now take the picture with perfect exposure.
The reflective light meter in your camera evaluates the brightness of the objects in the scene and thus will often lead to over- or underexposure. As a result photographs of snow scenes end up grey and pictures of black objects tend to be too bright.
An incident light meter sees the actual light and is a lot more precise. Unfortunately an incident light meter can also easily cost hundreds of dollars or more.