Alien Bees vs 580ex ii

[sactown024]

I currently run a 3 light setup using Canon 580ex ii, mostly using all 3 of them at once for receptions but really would like to start adding larger modifiers to my portrait lights, something like a 24x36 softbox. I am curious if 3 580's on a triple flash bracket would even come close to the power of say an AB800.

I am debating if i should spring for an AB/Einstein or save the money and just use a triple flash bracket. Would the 3 flashes even come close to the power of a AB800? If not, how many speedlites would it actually take to get the same power as an AB800?

I do understand that 3 flashes gains 1.5 stops of light, but I am lost when it comes to how much power comparison that is to a AB.

 

[beachrat]

You'd probably need 6 speedlights to equal the AB800 assuming you aren't firing them at full pop every time.
And,there's a pretty big difference between the AB800 and the Einstein.

 

[Big Mike]

It's fairly hard to compare the two (580 vs B800) because the modifier that you use makes a big difference.

If you are talking about shooting a 580 directly at your subject, especially if you zoom in the head, you get A LOT of usable light on your subject. It probably won't be as much as a B800 with the standard 7" reflector, but it may be as much or more than the B800 with reflector and umbrella.

The 580 can be really efficient because the head does a great job of constraining the light to a beam (especially if you zoom out the head). But as soon as you want to soften the light by putting it into an umbrella or softbox etc, you find that there is nowhere near as much overall light as you get from a 300 W/s studio light.

So, if you want to use a large softbox or umbrella etc., you'll end up with significantly more light by going with a studio strobe, rather than a 580EX (probably more than 3 580EX, but don't quote me on that).

You may find it limiting if you put all three of your 580s onto a stand, just more more power. I'd think that you'd have a lot more options if you have 3 or 4 separate lights.

 

[kathyt]

I am all speedlights at receptions. I hate dragging bigger crap around. What are you shooting with?

 

[Derrel]

I think of an SB 800 or a 580 EX-II as being about 60 Watt-seconds of power at the maximum, and I think of an AB 800 as a 300 Watt-second flash, tops. (I am thinking of the Paul C. Buff light units based on Speedotron's "old standard" 11.5 inch 65 degree beam spread reflector, which at 300 Watt-seconds has a GN similar to the AD 800 with the Paul C. Buff 11-inch, larger reflector.

Alien Bees Guide Number? - Photo.net Lighting Equipment and Techniques Forum

 

[beachrat]

I really think the only way to get a fairly accurate comparison would be with a meter.
The guide numbers I was using in my head are pretty close to what Derrel posted,but who knows how optimistic the manufacturers numbers are?

 

[hirejn]

The rule of thumb is one Speedlight is about 50 WS. So if the AB800 is 300 WS, then it's the equivalent of about six Speedlights. Not all WS are the same in use but it's a handy rule of thumb. But your question is moot if all you want to do is make a nice portrait with a soft box. Two or three Speedlights in that size soft box are plenty for a good portrait at say studio working distances. Then your lights are tied up into one unit so you'd have to buy more for more 3-D lighting if you wanted to add kickers or fill. ABs are inexpensive, but then you also need to buy a way to trigger and support them, and modifiers that fit, and a battery pack if you take them on location without outlets.