A45W Slave Strobe Flash: How It Works and When to Add One
By ephotoinc | Published: 2026-11-04
Category: ハウツーガイド
Learn how a slave strobe flash works, how to set up the A45W optical slave, and when adding one to your lighting kit makes sense. Includes sync tips and common mistakes.
Quick Answer
Use the A45W as an optical slave when you want a second light without running a sync cable: mount it on any AC screw adapter, plug it into a 110V outlet, and trigger it with your main flash. It adds fill or background light for about two seconds of recycle time, but it only works when its sensor can see the master flash.
What the A45W Does and Does Not Do
The A45W is a 45W slave strobe that fires when it detects another flash. It has no built-in radio receiver or sync port, so it relies entirely on line of sight to the master flash. That makes it simple and cable-free, but it also means the slave can miss triggers if the master is hidden or too far away.
Because the A45W recycles in about two seconds, it suits portrait or product setups where you are not firing in rapid bursts. If you need high-speed continuous shooting, a dedicated radio-triggered strobe is a better fit.
When Adding a Slave Strobe Makes Sense
Add an A45W when you already have one flash and want a second light for fill, a hair light, or a background wash without buying a radio trigger system. It is also handy in small studios where running cables is awkward.
Skip it if your master flash is mounted inside a softbox that blocks the slave sensor, or if you frequently shoot in bright ambient light where optical slaves can be unreliable. In those cases, a radio-triggered light is more dependable.
Step-by-Step A45W Slave Strobe Setup
- Mount the strobe: Attach the A45W to a light stand using an AC screw adapter. Make sure the stand is stable and the strobe is aimed at your subject or background. Check that the adapter is tightened; a loose mount can let the strobe shift during the shoot.
- Connect power: Plug the strobe into a 110V outlet. Keep the cord out of walkways and avoid daisy-chaining with other high-draw devices on the same circuit. Confirm the outlet is live before you rely on the slave; a dead outlet is a common silent failure.
- Position the slave sensor: Point the front of the A45W toward your main flash so its optical sensor can see the trigger. Avoid placing it behind the master or inside a softbox that blocks the light. If the slave does not fire, rotate it slightly or move it closer to the master until it triggers reliably.
- Set the master flash: Fire a test shot with your main flash. The A45W should trigger at the same time. If it does not, reduce the distance between the two or remove obstacles. Use a test shot before the session starts; do not assume the slave is synced.
- Adjust power and distance: Balance the slave’s output by moving it closer or farther from the subject. The A45W has a fixed 45W output, so distance is your main control. Take a test shot and check for blown highlights; adjust distance rather than adding diffusion if the slave is too bright.
- Check sync and recycle: Shoot a short burst to confirm the A45W keeps up. With about two seconds recycle time, wait between frames if you need full power. If you see dark frames, you are shooting faster than the strobe can recycle.
Product Facts
- Photo Slave Strobe Flash A45W: 45W slave strobe triggered by another flash, with about a two-second recycle time. It provides a simple cable-free second light, but the recycle time limits rapid shooting.
Photo Slave Strobe Flash A45W - Photo Slave Strobe Flash A45W: Works on any 110V power outlet and mounts on any AC screw adapter. You can place it almost anywhere there is a standard outlet and a stand with a screw mount.
