A dynamic vision sensor such as an event based vision sensor employs analog to digital converters (ADC), such as ramp ADCs, that analog to digital converts the signals from photoreceptors. Only previous light values need to be stored in the pixels. This is accomplished by generating three ramps. In addition, log compression can be implemented by increasing the count linearly while increasing the reference voltage exponentially, or increasing the count logarithmically while increasing the reference voltage linearly.