Interfit S1a HSS TTL Flash, AC only

SKU: INTS1A Categories: , , .

500Ws monolight with HSS and TTL for Canon, Nikon, and Sony.



Click HERE for the latest firmware updates for the S1a

The S1a is the AC-powered counterpart to the award-winning S1, and contains all of the same intelligent TTL and HSS technology.

  • Through The Lens Metering in TTL Mode uses the S1a’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 in the power range and is manually adjustable in 1/10-stop increments
  • Fast Recycle Time of only 2 seconds at full power allows for rapid shooting in a fast-paced studio environment.
  • 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 1/1000th of a second to 1/9000th depending on power output 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

Additional information

Maximum Watt/seconds


Power Range

9 Stops (2.0 – 10.0)

Full Power Recycle Time

2 Seconds

Flash Duration

1/1000 – 1/16,000 (max-min power)

Color Temperature

5700K +/- 100K

Fitting Type

Bowens® / S-Type

Modeling Lamp



Interfit TTL-C/N/S 2.4GHz Remote, Sync Port, IR/Optical

Shooting Modes

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

Maximum Flash Sync Speed

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

Operating Voltage

220-230VAC or 110-120VAC

Fan Cooling


Auto Power Dump


Flash Ready Indicator

LED and switchable audible


32 x 13cm (12.6 x 5.1″)


2.25Kg (4.9lb)

The Interfit S1a HSS TTL Flash, AC only includes:

  • 1 - S1a Flash Head
  • 1 - RF5003
  • 1 - 13' (4m) Power Cable
  • 1 - Micro-USB Cable
  • 1 - Sync Cable

Interfit S1a HSS TTL Flash, AC only Downloads


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