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


NOTE: The INTS1N and INTS1 are the same product. We have decided to remove the AC power pack from the box (to sell separately) and update the packaging since most customers weren't using the included AC. This allowed us to lower the price and offer a better value for customers who primarily shoot with our long-lasting battery.
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) | T.1 of 1/800

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


  • Bob Leverone Jun 23, 2020

    I have three S1’s and absolutely love them. The Canon Remotes I have work flawlessly. I have used both the AC power and DC power with no issues. Great light for the price.

  • Photo by Caz Dec 03, 2020

    Just know that that the S1 has all the features that you want and need for a price that you can’t beat.

    I have two Interfit S1 with Interfit lightboxes that are paired with an Interfit Sony remote and they are my go-to for all my photoshoots. The S1 has the power to light my clients in any demanding environment like shooting against direct sunlight and the control to make sure the lighting always fits the mood.

    I travel often with my Interfit kit and it has never failed to provide me with the lighting that I need. From shooting sunrises, mid-day, or even poorly lit locations; the S1 has been rock solid.

    Whenever I have any issues with my S1, which is always my fault because I am a bit rough with my gear, the customer support has always treated me the best. They always understand that my gear is my livelihood and work to get me back up and shooting.