Timelapse+ Auto Sunset Bramp Simulator

Chart showing values (y) over time (x)

Adjust the PID values below and press "update" to observe changes

Light Sensor Reading     Target Exposure     Calculated Exposure     P: I: D:  

Tuning concepts

The chart is created with real-world data from the Timelapse+, and uses the same algorithm for determining exposure. This makes for an easy way to test changes to the algorithm tuning without a several hour actual test. Higher values on the chart represent a brighter exposure/darker sky. The y scale is in stops, relative to the start of the bulb ramp.

Chart Values

Tuning Parameters

The Timelapse+ auto bramp algorithm is based on the PID controller. More info on the PID controller can be found here: http://en.wikipedia.org/wiki/PID_controller

The Timelapse+ controls the exposure value rate, not the exposure directly. This makes for smooth transitions and minimizes flicker in response to momentary changes in light. The Timelapse+ continuously "steers" the exposure to keep it on track. The following parameters determine how it controls the rate.

Code snippet from auto bulb ramp portion of shutter.cpp

This code can be edited for testing -- press update below the chart above to test changes to the algorithm.