According to the manual and expert reviews, the E-P3 was a significant milestone for the PEN series:
: The manual highlights "Frequency Acceleration Sensor" technology, which at its 2011 release was marketed as the world's fastest AF for interchangeable lens cameras.
: It features a 3-inch OLED touchscreen. The manual explains how to use "Touch Shutter" and "Touch AF" to focus and shoot with a single tap.