Since its introduction, Sekonic's L-358 Flash Master has become the best-selling digital flash meter in its class. Weather-sealed against the nastiest of working conditions, the L-358 delivers dead-nuts accurate flash and ambient light reading in both incident and reflected modes.For mixed lighting scenarios, the L-358 displays the combined exposure values of both flash and ambient light sources, including the percentage of flash in total exposure in 10-percent increments. Dual ISO buttons allow for quick exposure factoring when working with two differing film speeds, film and Polaroids, or other situations where comparison readings are desired.