Optimized for use with Leica's latest cameras, the SF 40 has TTL support for automatic exposure and metering and it features a compact design with a useful output. Rated with a guide number of 131' at ISO 100 and 105mm, this unit can easily illuminate a room or subject. Also, it has a zoom range of 24-105mm, which can be expanded to 16mm with the use of the pull-out diffusion panel, for excellent coverage with your lenses. On top of this, an LED video light with 9 output levels is available for lighting a scene for high resolution video capture.