Recent information concerning the electric field changes from lightning flashes have been employed to study the response of Conference Internationale des Grandes R¿seaux Electriques (CIGRE) and International Radio Consultative Committee (CCIR) lightning flash counters. This study led to the following conclusions: (1) The CIGRE 10-kHz counter operates on the radiation field of the return strokes, and the effective range of this counter is about 20 km. (2) The CCIR counter is similar to the CIGRE 10-kHz counter, except for its high sensitivity and the ability to react to radiation pulses of both polarities. The effective range of this counter is estimated to be about 140 km. (3) The effective range of the CIGRE 500-Hz counter is about 30 km. (4) A better discrimination between cloud and ground flashes can be achieved by raising the center frequency and low-frequency response of the CIGRE 10-kHz counter, while keeping the upper frequency response the same. The response to ground flashes remains approximately the same after the modification.