Mounting the Panasonic DMW-FL500 TTL external flash unit onto the L1 hotshoe gives you precise TTL light control of the high-powered flash, and lets you use the versatile functions of the flash. Linked with the L1's light-metering functions, the DMW-FL500 uses a TTL light adjustment system to measure the light that actually strikes the Live MOS sensor, then adjusts the flash intensity accordingly. The result is flash photos with outstanding exposure. The FL500 has a guide number of 50 (ISO 100/m). The angle zoom function covers a lens range of 24-85mm (35mm camera equivalent). Using the built-in wide panel further extends coverage to a view angle of 18mm. The firing angle can also be automatically changed to create a bounce lighting effect.