With the introduction of the of the S1 AC/DC HSS TTL Monolight from Interfit, the company elevates its place in the ever-widening group of manufacturers producing TTL monolights.
The flash head is powered by an internal, removable 4500mAh lithium-ion battery that fits inside the head's housing. It has a 350 full-power flash capacity and can also run on an optional AC adapter while your battery is charging. It's controllable wirelessly at distances up to 328'.
The S1 has 3 shooting modes: Wireless TTL for Canon, Nikon, or Sony; Manual Mode; and High-Speed Sync. Wireless requires purchase of a Nikon, Canon, or Sony dedicated transmitter, but once that's done, you can basically treat these studio strobe units as you would your on-camera flash. In TTL, the camera's flash technology takes stock of the scene and automatically adjusts the power from 1.9 to 500Ws across a 9-stop range. If you want to fine tune your exposure, there's +/-3 stops exposure compensation adjustable in 1/3 stops.
Traditional manual mode is available for those who want complete control. Manual mode (1/250 sec) is also how you access HSS (High-Speed Sync). This mode uses the flash's top 3 power levels (from 125 to 500Ws) to allow you to access sync speeds as short as 1/8000. HSS presents a new world of exposure possibilities whether you're trying to overpower the sun, control the background's brightness, or use wider apertures.
The S1 recycles to full power in 3 seconds and a fraction of that time at reduced power levels. Thanks to the incorporation of IGBT technology, the flash can also reach flash durations as short as 1/11,000 sec for the ultimate in stop-action while still maintaining a steady 5700K color temperature.
The S1 ships as a complete system including a 350-shot lithium-ion battery with a charger that powers it up in about 3 hours. Since the S1 is AC/DC, it can also be plugged into a wall outlet for use via a separately-purchased AC adapter regardless of its voltage while the battery is charging. The S1 also includes a 7" Bowens S-Type reflector, and a mini USB cable.