Paul C. Buff, Inc. Technical Forum

Is it possible for the slave sensors in AlienBees to LOSE sensitivity over time?

I have two B400's that I use at wedding receptions. I have been using them slaved to an on-camera speedlite. This lets me drag the shutter and pop the Bees with the Speedlite's second curtain sync. Usually I have the speedlite pointed at the ceiling. Or at an outdoor or exceptionally large venue, I'll put a diffuser on the speedlite and point it forward.

This had been working fantastic. Except for the last several months.

Now the Bees refuse to fire for anything but a bare flash aimed directly at the unit. And I do mean DIRECTLY pointed at the Bee. If I use a bare flash, full power, no more than 20 feet away, and I'm even SLIGHTLY off-axis from direct line of site to the Bee, the slave will not trip. It's driving me crazy.

Even shooting in venues I have been in before -- and had this setup work flawlessly -- I'm having nothing but troubles. And I know that NOTHING has changed in regards to gear or set up (same distance, same room size / ceiling height, same speedlite on camera, etc.).

Any ideas?

Plausible, but unlikely. More likely is a build up of dirt on the slave eye window, and possibly the slave eye itself. Also, light entering the vents can set off the slave, so if those are newly blocked for any reason, that may change behavior. Also, changes in modifiers can change the path light needs to take in order to trigger the light.