Paul C. Buff, Inc. Technical Forum

Hello, I just recieved 2 alienbees B400 and having quite a sad time... One of it has broken in 10 minutes of use so I have to ship it back to UK, but I started to play with the other one and here's what I have:

- using it with a wireless trigger, Canon 6d, manual mode, 125 shutter speed, f8, reflective black-white walimex pro umbrella.

I'm taking 5-6 photos from the same position, with the same amount of power (tried full power and 1/2 power), not very fast (the tracking light indicates that the unit is ready for each shot). And when I view the photos, there's a slight color inconsistency from shot to shot, bearly noticeable. But there's also a light inconsistency, especially there's a difference between the first shot and the others. And this one, I can notice it just with my eyes.

Is it an issue with all alienbees (I've read about it in forums but it concerned mostly operating in low power settings) or my second unit is also malfunctionning and I just have a bad luck ?

Thank you.

As for the color, what white balance setting are you set to? If set to Auto white Balance, set it to flash or sunny and see if the problem persists. Ideally, you would set a custom white balance, but that is not necessary for this trouble shooting exercise.


Also, what ISO are you using? Are there any Dynamic Range assisting features that may be turned on in the camera?

I'm using a custom 5300K WB, shooting on ISO 50, also tried on 100. Dynamic range or other features are disabled on my 6D.

Additional information:

when using B400 starting with 1/8 power and further down, the light inconsistency becomes really big, judging by my eyes, every 1 of 4 shots (with the same power setting) is about 1 stop of light less then other shots. Is it normal ? Also on 1/8 power photos get a reddish/yellowish tint (or maybe it's just the color temperature which changes).

And I'm not so worried about the color inconsistency, even if it will get weird results with two B400s set at 1/1 and 1/8 power each in a same set. I'm more worried about light output inconsistency1. Is it normal ?

No, a power shift shooting slowly is not normal. If you look on the back of the light, the green LED should light up when recycled. Once fired, it should come back on in about 1/2 second. Is it doing this, or is it taking longer?

Do you have a flash meter to test the actual output?

Are you using AC mains from the wall, or a different AC source (i.e. power pack)?

What kind of wireless remotes are you using?

The green light lights up quick as it should do depending on power setting.
Unfortunately I don't have a flash meter.
I'm using grounded AC mains from the wall.
And as a trigger I'm using Yongnuo YN 622C which works just fine.

Then there may be something in the charge circuit. The color shift would come from the power shift, as color is a function of power (given the same tube and flash unit).

As long as the green ready light is on on the back panel, then each shot should be equally exposed and the same color.

Unfortunately, it seems you will need to discuss getting this light swapped with PCB EU as well.