Interfit USA | S1 HSS/TTL, AC/DC Flash
Euro/UK site
Flash S-Series Featured


S1 HSS/TTL, AC/DC Flash image

The S1 is the first high-tech TTL HSS monolight to include intelligent TTL and HSS technology in a battery-powered monolight with an available International Multi-Voltage AC Power adapter.

  • Through The Lens Metering in TTL Mode uses the S1’s entire 9-stop power range (500W – 1.9Ws) and is automatically calculated in 1/10th stop increments, and allows for ± 3 stops of exposure compensation
  • Manual Mode utilizes the entire 9-stop power range, controllable in 1/10th stop increments
  • High-Speed Sync in Manual Mode at up to 1/8000th of a second shutter speed using the top 3 stops of the power range (10.0 – 8.0) and is manually adjustable in 1/10-stop increments
  • Available International Multi-Voltage AC Adapter that can power the unit with or without the battery in place, maximizing battery health longevity
  • Integrated and exchangeable lithium-ion battery is flush with the flash body, offers a 350 full power flash capacity and allows for wire-free and rapid setup and repositioning of lights when power outlets encumber workflow or are not an option at a shoot
  • Color Accurate to within ±100 Kelvin using high-tech insulated-gate bipolar transistor (IGBT) technology
  • Short Flash Duration for freezing action and sports motion between 1/500th of a second to 1/11000th without compromising color consistency, using IGBT technology.
  • Integrated Wireless System with remote TTL flash exposure compensation and manual power control in three groups from camera position using the S1 Remotes for Canon, Nikon, or Sony (sold separately)
  • Frosted Glass Dome softens and disperses light evenly through large and small light modifiers alike, from large octaboxes to small beauty dishes and reflectors while protecting the user-replaceable flash tube.
  • Aluminum Construction with an attractive matte finish gives the unit greater heat dispersion, durability and weight-to-rigidity efficiency
  • Firmware Upgradeable via Micro USB Port for future fixes and features
  • Bowens® S-Type Mount is compatible with a large scope of adapter rings and modifiers such as softboxes, reflectors, and grids
Maximum Power:


Power Range:

9-Stops (500Ws – 1.9Ws)

Recycle Time at Full Power:

3 Seconds

Flash Duration:

1/500 – 1/11,000 (max-min power)

Color Temperature:

5700K +/- 100K

Modifier Mount:

Bowens S-Type

Modeling Lamp:



Interfit TTL Remote for Canon
Interfit TTL Remote for Nikon
Interfit TTL Remote for Sony
Interfit Manual Remote for all cameras
Sync Port

Shooting Modes:

Manual, TTL (Canon/Nikon/Sony), HSS

Maximum Flash Sync Speed:

1/250sec. in standard sync mode, 1/8000sec. in high-speed sync mode

Operating Voltage:


Battery Type:

4500mAh Li-Ion

Battery Life:

350 full power flashes

Battery Recharge Time:

3 Hours

Flash Ready Indicator:

LED and switchable audible


13.4” × 9.1” × 5.1”



  • [1x] S1 Flash Head
  • [1x] Protective Cap
  • [1x] 7" Reflector
  • [1x] Battery For S1
  • [1x] S1 Battery Charger
  • [1x] Micro-USB Cable
  • [1x] PC Sync Cable

Write a Review


  • Robert Trawick Nov 12, 2018

    Durable, Consistent, Easy to Use –
    After almost four years of pro use, my S1 lights are part of my daily work and are integral to my success in lighting anywhere at any time. While I don’t recommend purposely dropping any equipment, my lights have survived multiple falls and continue to function despite the little mishaps of professional use. They provide consistent, repeatable light output while maintaining color temperature even during high-speed flashing. The S mount is the most stable and easily changed adapter on the market with a wide range of available light modifiers. The large LCD screen is easy to read and the numbers correspond to stops of light that make it easy to adjust settings for scene changes. The battery seems to last all day of multiple sessions but the AC adapter makes shooting in a studio a breeze saving your battery for on-location shoots. The only way they could make this unit better would be a special “RED” painted version or maybe a royal purple!

  • Jeremy Ellsworth Feb 28, 2019

    I wanted to let you know directly how much I love my S1! I have had it for a little over 2 weeks and have used it in studio and on location during a wedding. It worked flawlessly in both environments.

    I have been using Paul C Buff Alien Bees for my off camera work since I learned OCF. To now have a light that allows me to power, versatility, and consistency, all while wireless, is a HUGE benefit over my previous set up.

    I will certainly be telling everyone I know about Interfit and this light. I look forward to adding additional Interfit lights to my arsenal in the future as well.

    So thank you for creating such an extraordinary piece of equipment.