How to Pair the Westcott FJ400 II With the FJ-X3 S Trigger

By Dodd Camera | Published: 2026-10-16

Category: How-to Guides

A step-by-step guide to pairing the Westcott FJ400 II with the FJ-X3 S Sony trigger, including sync speed, HSS, and battery tips.

Quick answer

To pair the Westcott FJ400 II with the FJ-X3 S Sony trigger, set the FJ-X3 S to the same channel and group as the strobe, then confirm the link. For Sony bodies, use HSS when you need shutter speeds above the camera's native sync speed. Keep the FJ400 II battery charged and the trigger firmware current for reliable off-camera flash.

Set up the FJ-X3 S Sony trigger first

Mount the FJ-X3 S on your Sony camera's hot shoe and power it on. The trigger is the control point for channel, group, and power, so configure it before touching the strobe. If the trigger menu feels unfamiliar, work through it slowly the first time; after that, the layout becomes quick to navigate.

Match channels and groups on the FJ400 II

On the FJ400 II touchscreen, set the strobe to the same channel and group you selected on the FJ-X3 S. If you plan to use multiple lights, assign each one its own group so you can adjust power independently from the camera position. This is the core of a reliable Westcott strobe trigger pairing.

Confirm the link and test fire

Use the trigger's test button to fire the strobe. If it does not fire, recheck channel and group, then confirm the strobe is not in a slave or optical mode that conflicts with radio triggering. A quick test fire before you start shooting saves troubleshooting later.

Set sync speed and enable HSS when needed

Start at your Sony camera's native sync speed, then enable HSS on the FJ-X3 S if you need faster shutter speeds for wide apertures in bright light. HSS with the FJ400 II reduces effective output, so plan to move the light closer or raise power. If you see banding or dark edges, drop back to the native sync speed and adjust exposure another way.

Battery habits that keep the FJ400 II ready

Charge the FJ PRO AC/DC battery fully before a shoot and top it up between sessions rather than running it to empty. If you are working near power, the AC/DC design lets you run from AC, which saves battery cycles. For travel, carry a second battery if your shoot runs long or you use HSS heavily.

Pairing steps with checkpoints

Mount and power the FJ-X3 S: Slide the FJ-X3 S into your Sony camera's hot shoe, tighten the locking ring, and turn it on. Set the trigger to radio mode, not optical. Checkpoint: the trigger screen should show a channel and group before you move to the strobe.
Set the same channel and group on the FJ400 II: On the FJ400 II touchscreen, choose the channel and group that match the FJ-X3 S. If you use two strobes, give each a different group. Common mistake: leaving the strobe on a different channel than the trigger, which causes no-fire.
Test fire and confirm exposure: Press the test button on the FJ-X3 S. The FJ400 II should fire immediately. If it does not, recheck channel, group, and that the strobe is in radio receive mode. Checkpoint: a clean test fire at your starting power before you shoot.
Set sync speed, then enable HSS if needed: Begin at your Sony camera's native sync speed. For faster shutter speeds, turn on HSS on the FJ-X3 S and expect lower effective output from the FJ400 II. Common mistake: leaving HSS on indoors, where it wastes power and can cause inconsistent color.
Manage the FJ PRO AC/DC battery: Charge the battery fully before the shoot. If you are near AC power, run the FJ400 II from AC to preserve battery cycles. For long HSS-heavy shoots, carry a spare. Checkpoint: battery level above 50% at the start of a paid session.

Products used in this setup

WESTCOTT FJ400 II Touchscreen Strobe with FJ PRO AC/DC Battery: The Westcott FJ400 II Touchscreen Strobe redefines portable lighting with unmatched speed, reliability, and color accuracy. The touchscreen makes channel and group changes quick, which matters when you are pairing and adjusting power on location.
Westcott FJ80-SE S 80Ws Speedlight for Sony Cameras: Enhance your photography with this powerful 80Ws round head Sony camera speedlight, delivering 550+ flashes per charge, even light coverage, and easy operation. A Sony-dedicated speedlight like the FJ80-SE can serve as an on-camera fill or backup while the FJ400 II handles key light.
WESTCOTT FJ400 II 2-Light Backpack Kit with FJ-X3 S Sony Trigger: The Westcott FJ400 II Touchscreen Strobe redefines portable lighting with unmatched speed, reliability, and color accuracy. The 2-light backpack kit includes two FJ400 II strobes and the FJ-X3 S Sony trigger, so you can pair both lights to separate groups for more control.