The Interfit S1 Monolight Offers TTL with Canon and Nikon DSLRs


It looks like the world of monolights are getting some new competition when it comes to TTL metering transmission. Profoto was the first to the pot, then Phottix and now Interfit with their new S1. The Interfit S1 is a 500ws monolight that they’re stating does both TTL transmission and HSS (high speed sync) with Canon and Nikon DSLRs.

The Interfit S1 can work function by either using a battery pack or AC power connectors, and the company claims that their 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. Said battery seems to be incorporated into the body of the monolight in the same way that Profoto does with their B1.

The Interfit S1 has a 7 stop power range and these can be dialed up/down in 1/10ths of a stop. When shooting in HSS, the TTL transmission can be dialed in in up to 1/3rd stops. This light also offers a very fast flash duration at 1/19,000th at minimum power and 1/1,000 at full power.

More tech specs and images are after the jump, and when the Interfit S1 launches in early December, the package will retail for $999.





Specifications S1 S1a
Maximum Watt/Seconds 500Ws
Guide Number

100ISO, 1/125sec., 3m (10’)

48.7m (160’)
Flash Power Range 7 Stops (2.0 – 8.0)
Flash Variability 1/10th stop increments
Recycle Time 3 sec. (AC & DC) 2 sec.
Flash Duration 1/1,000 – 1/9,000 (max-min power)
Color Temperature 5700k +/- 100k
Modeling Lamp 10w LED (off, 50%, 100%)
Wireless Control Interfit TTL-C/N 2.4GHz Remote

Sync Port, IR/Optical

Shooting Modes Manual, TTL (Canon/Nikon), HSS
Maximum Sync Speed 1/250 sec. In normal sync mode

1/8000 sec. in High Speed Sync mode

Operating Voltage 100-240 VAC 110 VAC or 220VAC
DC Battery Type 4500mAh Li-Ion
Battery Life 350 full power flashes
Battery Charge Time 3 Hours
Fan Cooled Yes
Auto Dump Yes
Temperature Regulation Yes
Dimensions (Length x Diameter)

Inc. glass dome and handle

34 x 13cm

(13.4 x 5.1”)

32 x 13cm

(12.6 x 5.1”)


Inc. battery (S1 only)






Interfit S1 AC/DC TTL and HSS Flash – $999.99


Chris Gampat

Chris Gampat is the Editor in Chief, Founder, and Publisher of the Phoblographer. He also likes pizza.