So a few months ago I picked up one of these brand new Interfit S1's, and wanted to give it a spin to see how well it held up. These were brand new to the market, and STILL haven't really been reviewed online, so I figured I'd make something applicable to most photographers, instead of just specs.
Check out the video:
Here's the link to Interfit's site:
http://interfitphotographic.com/product/interfit-s1-acbattery-powered-hss-ttl-flash/
Since there will obviously be a ton of people wanting the specs of each unit to compare the two, here ya go. Pulled from B&H:
Profoto B1
Maximum Watt/Seconds: 500W/s +/- 1/20 Stop
Flash Variability: In 1/10 or 1 Stop increments 9.0 Stops:
2.0-10 power level (1/256-1/1)
2.0-500W/s
Recycle TimeMinimum/Maximum: 0.1-1.9 sec.
Quick Burst Mode: 20 frames per sec.
Flash Duration: Normal mode (t0.5): 1/11,000 - 1/1,000 sec. min/max power
Freeze mode (0.05): 1/19,000 - 1/1,000 sec. min/max power
Color Temperature: 5,600K
Modeling Light Control: Off / Proportional / Free (full) 5.0-100%
Max Sync Speed: Up to 1/250 sec. in normal mode
Up to 1/8,000 sec. in High Speed mode (requires free firmware update)
Wireless Remote: Yes, via optional Air Remote TTL-C/N, Air remote, Air USB (Profoto Studio) Wireless range:
Up to 1,000' (300 m) for normal triggering
Up to 330' (100 m) for TTL with optional Air Remote TTL-C
Frequency Band: 2.4 GHz
Triggering: Air radio slaves, optical (IR), sync cord
Operating Voltage: 100-240 VAC, 50/60 Hz, Self-sensing
14.8 VDC/3 Ah via included, rechargeable battery
Battery Type: Lithium-ion
220 Full power flashes Battery life: 300 charge cycles (to 80% left)
Battery Charge Time: 2.0 Hours with included 2.8V multi-voltage charger
Fan Cooled: Yes
Auto Dump: Yes
Auto Power Off: Yes, after 60 minutes of disuse
Sleep mode after 30 minutes of disuse
Flash Ready Indicator: Beep tone, ready right, modeling light dimming
Battery Charge Display: Green LED indicators: 3 Sections: 100-70%
2 Sections: 70-40%
1 Section: 40-10%
1 Section blinking
< 10%
Circuit Protection: Adaptive thermal control
Operating Temperature: 14 to +122°F (-10 to +50°C)
Storage: 4 to +140°F (-20 to +60°C)
Dimensions: Length x diameter:
Body only: 12.2 x 5.12 (310 x 130 mm)
With 5/8" (16 mm) stand adapter: 12.2 x 6.69" (310 x 170 mm)
Weight6.61 lb (3.0 kg) Including battery
Interfit S1
Maximum Watt/Seconds: 500Ws
Wireless Range: 300' (100 m)
Flash Variability: 7.0 Stops (2.0 to 8.0) in 1/10 stop increments
Recycle Time: Maximum 3.0 sec.
Flash Duration: 1/1000 - 1/9000 sec. min/max power
Color Temperature: 5700 K +/-100 K
Modeling Light: 10W LED
Modeling Light Control: Off, 50%, 100%
Flash SyncNormal: 1/250 sec.
High-Speed Sync: 1/8,000 sec.
Wireless Remote: Built-in Receiver
Optional Interfit TTL-Canon/Nikon 2.4 GHz Remote
TriggeringWireless remote, sync cord, IR/optical
Operating Voltage: 100-240 VAC, 50/60 Hz
Included battery
Battery Type: 4500 mAh lithium-ion
350 full-power flashes in Manual mode
400 full-power flashes in HSS mode
Battery Charge Time: 3.0 hours with included multi-voltage charger
Fan Cooled: Yes
Auto Dump: Yes
Dimensions: Length x Diameter:
With Dome and Handle: 13.4 x 5.1 (34 x 13 cm)
Weight6.3 lb (2.85 kg) including battery
Now that the tech specs and mumbo jumbo is over....here is where the application comes in.
I have been using the S1 as my main light for the past few months, and it has been a staple so far for my camera gear bag. The light is beautiful (I know a modifier has an influence on this). I still can't get over how portable a strobe can be without having battery packs...but nonetheless...it's still good with that feature aside. I usually shoot with just one light, and maybe a few extra's for a rim light, or to emphasize some ambience. So when I pack my camera bags for an assignment, I have been using this thing non stop as my main choice.
I have a few different light modifiers I have been using with the S1. The main 3 are these:
26" White beauty dish
36" Reflective diffused umbrella
39" Selens deep parabolic umbrella
I choose these three main umbrellas simply because of the portability of each (the same reason I picked this strobe). Each of these easily fold up or fit into the suitcases I travel with. I'm also not usually shooting more than 2 people per image when I shoot, so something this size is perfect for my needs. I also bring with me the zoom reflector that comes with the unit, but I personally don't ever use it, or have the need for it, unless I just want to use the unit as a strong backlight.
I personally really like using the beauty dish for its simplicity of a portable unit. It's 500w that you can hand-hold and walk around with. When I use the dish, I use the diffusion sock to soften the light a little more, and it's just as soft as the other two modifiers...just with a much bigger spread.
Here's a selection of images I've made over the past few months with the Interfit S1:
S1 as main light through the 36" umbrella. Side lights are speed lights with gels. One speed light behind subject up near the roof, pointed down to brighten the chalk.
S1 as main front light, shot through the 39" Selens. One speed light on each of the sides to highlight edges.
S1 shot through 26" beauty dish with diffusion sleeve. Light positioned above camera.
S1 shot through the 39" Selens to camera left.
S1 shot through a 60" silver parabolic umbrella. This is another umbrella I own that I use on occasion.
S1 shot through the 36" umbrella to camera right.
S1 as main light to camera right, shot through the 39" Selens. Speed lights on each side, and above from rear to highlight edges.
S1 shot through the 36" umbrella to camera left. One speed light in the right side towards the back of the room as fill.
S1 shot through the 39" Selens to camera left.
S1 shot through the 36" umbrella to camera left. One speed light to the right to highlight the bag/leg.
I've heard before that because of the minimum power output of this light, it can be hard to use in a dark setting. So this photo was made with the S1 at its lowest setting. Camera settings were 1/160 sec, f/7.1, ISO 800. The Selens umbrella is double diffused (the inner baffle removes any possible hotspot). So if this is still too much light for a dark ambient setting, you can always just get some ND gels and put that over the bulb.
Here's the link again to their site:
http://interfitphotographic.com/product/interfit-s1-acbattery-powered-hss-ttl-flash/
Hope this sheds a little more light on this new strobe. I think its worth it.
UPDATE*
I was recently shipped out a new remote for the strobe that has some updates that extend the battery life significantly. There has also been a firmware update that allows you to use TTL within the HSS, and more camera compatibilities.
-B