AB400 + Large Octabox = enough power?

Would the AB400 be sufficient for the large Alienbee octabox? Enough power to light groups of like 2-6 people? Full length?

I plan on getting two AB400s; one through the octabox for key, one on an umbrella for rim, and my 580 EX for fill/additional rim. Plus reflectors & translucent diffusers to soften the sun & fill as needed.

Thoughts?

I shoot my WL1600 indoors in half power mode (same power as AB400) with a large octabox all the time. You will probably be wanting more power if you shoot outside though. Any reason you don't get one AB800 and one AB400? The bottom line is that it depends what and where you will be shooting.

doidinho wrote in post #7097818
I shoot my WL1600 indoors in half power mode (same power as AB400) with a large octabox all the time. You will probably be wanting more power if you shoot outside though. Any reason you don't get one AB800 and one AB400? The bottom line is that it depends what and where you will be shooting.

I'll also be shooting sports with 4 AB 400s because they offer a better flash duration in comparison to the AB800. The AB800s have slower recharges, slower flash duration, and put out more power than I need for most uses.

doidinho wrote in post #7097818
I shoot my WL1600 indoors in half power mode (same power as AB400) with a large octabox all the time. You will probably be wanting more power if you shoot outside though. Any reason you don't get one AB800 and one AB400? The bottom line is that it depends what and where you will be shooting.

While it would SEEM that the WL1600 should be more than 2x the Alien Bee B400, this appears to be resultant from the days when Buff more optimistically called the WL flashes by even more optimistic names. If you look at the specs, Buff says WL has a GN236 rating (10' f/23) while the AB400 is about GN170 (10' f/16 + 0.2EV), so AB400 is indeed half the power as stated by diodinho.

If we assume a -1EV loss of light due to the light modifier, then we have 10' at f/8 with the AB400 in Octabox (an estimate, in case actual owner-measured output is later added in another post) or GN80. Which means that at 14' distance to the subject, you need to shoot at f/5.6 if shooting ISO100.

Wilt wrote in post #7097882
While it would SEEM that the WL1600 should be more than 2x the Alien Bee B400, this appears to be resultant from the days when Buff more optimistically called the WL flashes by even more optimistic names. If you look at the specs, Buff says WL has a GN236 rating (10' f/23) while the AB400 is about GN170 (10' f/16 + 0.2EV), so AB400 is indeed half the power as stated by diodinho.

If we assume a -1EV loss of light due to the light modifier, then we have 10' at f/8 with the AB400 in Octabox (an estimate, in case actual owner-measured output is later added in another post) or GN80. Which means that at 14' distance to the subject, you need to shoot at f/5.6 if shooting ISO100.

Cool - I plan on shoot at around f/6.3, with ISO 200-400. These are for canvas prints about 16x20" - on a 40D I don't think the ISO will print out too bad. I also have NoiseNinja so this should work out well?
You're calculations are based on a single light - I guess adding another two lights + reflectors and a diffuser will only help provide more than enough light!

In my quick testing with AB800 at 1/2 power, I get f8 at ISO100 at a distance of 8-10 feet. I am using photoflex 5' octodome with both internal and outer diffusion panels.

Wilt wrote in post #7097882
While it would SEEM that the WL1600 should be more than 2x the Alien Bee B400, this appears to be resultant from the days when Buff more optimistically called the WL flashes by even more optimistic names. If you look at the specs, Buff says WL has a GN236 rating (10' f/23) while the AB400 is about GN170 (10' f/16 + 0.2EV), so AB400 is indeed half the power as stated by diodinho.

If we assume a -1EV loss of light due to the light modifier, then we have 10' at f/8 with the AB400 in Octabox (an estimate, in case actual owner-measured output is later added in another post) or GN80. Which means that at 14' distance to the subject, you need to shoot at f/5.6 if shooting ISO100.

I think he meant the 1/4 mode, which is 165 actual WS, just like the AB400.

I could be wrong, he could have mean at the 1/2 power setting which would be equal to an AB800 at full blast. The fact that he said "mode" leads me to believe me meant 1/4 mode. Which turns off alot of the caps inside to have a super consistent output at 165WS, then you can adjust 1/2, 1/4 and 1/8 of that power before you start getting into inconsistent territory.

epatt250 wrote in post #7098142
I think he meant the 1/4 mode, which is 165 actual WS, just like the AB400.

I could be wrong, he could have mean at the 1/2 power setting which would be equal to an AB800 at full blast. The fact that he said "mode" leads me to believe me meant 1/4 mode. Which turns off alot of the caps inside to have a super consistent output at 165WS, then you can adjust 1/2, 1/4 and 1/8 of that power before you start getting into inconsistent territory.

No he meant what he said...and I took the output data from the Buff web sites...

WL1600 = GN236, AB400 = GN 170 or so,
236/170 = 1.4 approximately, or AB400 = 1/2 WL1600