Interfit S1 AC/DC HSS TTL Monolight

Interfit S1 AC/DC HSS TTL Monolight
Key Features
  • 1 x S1 500Ws Flash Head
  • 1 x Li-Ion Battery and Charger
  • 1 x Bowens-Mount Reflector
  • Optional Canon/Nikon/Sony Transmitter
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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.
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Interfit S1 Overview

  • 1Description
  • 2Compatibility and Firmware Updates
  • 3Complete Package
  • 4S1N TTL Remote
  • 5Power Supply
  • 6Shooting Modes
  • 7Manual Mode and High-Speed Sync
  • 8IGBT

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.

Compatibility and Firmware Updates

In order to ensure maximum compatibility with your system, Interfit offers firmware updates for download on their website. These updates can be easily installed by the user by connecting the monolight to their computer over USB.

Complete Package

500Ws monolight with High-Speed Sync, TTL for Canon and Nikon, IGBT technology, and a lithium-ion battery and charger in one complete package.

S1N TTL Remote

The S1's TTL remotes give the users direct control over any S1 light in any shooting mode from the camera position. This camera-mounted transmitter is available for both Canon, Nikon and Sony cameras. Having three individual groups gives users the freedom to control lights individually to create dynamic lighting ratios with a working range of up to 300' / 100m.

Power Supply

Each Interfit S1 comes standard with both battery and charger . The interchangeable 4500mAh Li-ion battery provides up to 350 full power flashes in Manual and TTL modes and over 400 full-power flashes in High-Speed Sync mode. This wire-free power source gives photographers the freedom and mobility to venture out from the studio and rapidly set up and reposition lights on location. For traditional studio work, the there is an optional AC power adapter available. This multi-voltage (100-240V) adapter can be used anywhere in the world and lets photographers continue to shoot while their battery is charging.

Shooting Modes

The S1 has three different shooting modes, each to serve a different purpose and shooting style. Interfit's S1 Remote for Canon, Nikon or Sony enables photographers to take advantage of their camera's TTL system just like they would with a speedlight. This automated light output uses the S1's entire 9-stop power range (500W - 1.9Ws), is automatically calculated in 1/10th stop increments, and allows for +/-3 stops of exposure compensation.

Manual Mode and High-Speed Sync

For those that prefer to have complete control of their light and have time for fine-tuned adjustments, the S1 can be used in the traditional manual mode. Manual shooting mode also utilizes the entire 9-stop power range, controllable in 1/10th stop increments. While in 1/250 sec. manual mode, users can access the S1's High Speed Sync mode, reaching shutter speeds up to 1/8000th of a second. High-Speed Sync mode utilizes the top 3 stops in the power range (500 - 125Ws) and is manually adjustable in 1/3-stop increments.


Utilizing IGBT technology, the S1 is able to offer short flash durations while maintaining color accuracy throughout the power range. Flash duration ranges from 1/500 at full power, to 1/11,000 at minimum power. While shortening the flash duration, Interfit was also able to improve color accuracy, giving the S1 a consistent 5700K (+/-100K) color temperature throughout the entire power range

Interfit S1 Specs

Flash Head
Maximum Power500 Ws
Power Control9 Stops in 1/10-Stop Increments
Guide Number160' / 48.7 m at 9.8' / 3 m, ISO100
Flash Duration1/11,000 to 1/500 Sec
Recycle Time3 Sec (Full Power)
Color Temperature5700K ± 100K
Accessory Fitting TypeBowens S Type
Modeling Light
Wattage10 W
Control ModesFull On, Off
Sync TypeCable, Infrared, Optical, Radio
Built-In Wireless ReceiverYes
Sync Speed1/1/250 Sec (Normal)
1/1/8000 Sec (High-Speed)
Wireless Frequency Bands2.4 GHz
Wireless Range328' / 100 m (Radio)
AC Input Power100 to 240 VAC, 50 / 60 Hz
Battery ChemistryLithium-Ion
Capacity (mAh)4500 mAh
Flashes Per Charge350 Flashes (Full Power)
Recharge Time3 Hours
Auto DumpYes
Fan CooledYes
Dimensionsø: 5.1 x L: 13.4" / ø: 13.0 x L: 34.0 cm, Including Handle
Weight6.3 lb / 2.85 kg, Including Battery
Packaging Info
Package Weight10 lb
Box Dimensions (LxWxH)21 x 11 x 10.5"
See any errors on this page? Let us know


Does this run off AC power without the battery ...

Does this run off AC power without the battery attached?
Asked by: Elizabeth
I always keep the battery attached. To run on AC you need to have the AC power unit plugged in to the head and the switch on the head set to AC.
Answered by: Lanny
Date published: 2021-02-08

Will the Godox XproS wireless trigger for work ...

Will the Godox XproS wireless trigger for work with this? All features compatible including HSS and TTL?
Asked by: James
No, it doesn’t work i tried this morning, but interfit s1 had a function cell if you set it ON it works, but it doesn’t recognize hss and ttl, thath is mi experince if someone else had different, please let me know, also my interfit trigger is for canon, probably if i can trie with sinc cord but I do not have one, sorry.
Answered by: Gumaro
Date published: 2021-01-31

does this light fit on a 5/8" boom mount?

does this light fit on a 5/8" boom mount?
Asked by: Jeffrey
Yes. The mount is a standard 5/8 socket
Answered by: Adrian
Date published: 2021-01-15

I have the S1 and the old TTL remote for Canon ...

I have the S1 and the old TTL remote for Canon (before there was a universal one) I have just upgraded the firmware which says it adds Canon R. Does anyone know if this will work and will be safe to use on a Canon R5?
Asked by: Howard
It will Be a firmware update.
Answered by: Werner
Date published: 2020-12-31

How do I get this to work with my Nikon D850?

How do I get this to work with my Nikon D850?
Asked by: Michael
You need to purchase the Nikon remote transmitter for the camera hotshot (B&H # INRS1N MFR # INTR1N)
Answered by: Brian
Date published: 2020-11-02

can anny one help me make a decision I need ...

can anny one help me make a decision I need lights for a studio and off set what would you guys recommend the interfit badger or the interfit S1!?
Asked by: Julio
The S1 is more powerful and more accurate than the Badger.
Answered by: Reuben
Date published: 2020-10-26

Trying to used a Yongnuo external flash with the ...

Trying to used a Yongnuo external flash with the interfit S1. Is it possible ?
Asked by: ANITA
I did it Thank you all for your help. Took me awhile. Many Thanks.
Answered by: ANITA
Date published: 2020-09-12

How low can this output? My only problem with the ...

How low can this output? My only problem with the Honey Badgers is they couldn't go as low as I wanted to just add a small bit of light and don't want that again.
Asked by: JASON
Hi Jason, The power range for the Interfit S1 is 1.95-500ws versus 5-320ws for the Honey Badger.
Answered by: byron
Date published: 2020-09-10
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