In what circumstances would the extra power of the 580 EX II or 600 EX be necessary?

Just wondering, for events and such, when would the extra power from the 580 EX II or 600 EX necessary as opposed to the 430 EX II?

The only thing I can think of is if you're bouncing off extremely high or dark-colored ceilings or shooting from far away, both of which can be easily fixed by repositioning yourself of bouncing off a wall (or even using direct flash if necessary).

Shooting mid day when you need every ounce of power to try and overcome the sun.

Pretty much anytime outdoors before dusk.

The output for the 580EXII and the 430EXII are almost identical when shot into a modifier like a 60" reflective umbrella.

How are you going to use it and with what modifier. Straight up direct unmodified flash is where you'd see the difference.

That's my experience.

To me, the supposed extra power is not the reason to go with the 580, it's a number of other features.

windpig wrote in post #14221574
That's my experience.

Mine too. Any situation where the 430 won't get the job done is almost always a situation where the 580 is going to fall short as well.

And again, I agree 100%.

There are likely very few situations where the power of the 430EX II is insufficient, but the power of the 580EX is sufficient.

The power difference is far less than one stop.

Changing your ISO on the camera from 100 to 200 would produce a greater effect.

Enjoy! Lon

If you were shooting at ISO 400 (to keep digital noise to a minimum) the 430EX would permit you to reach 35' with 105mm lens at f/4; the 580EX would permit you to reach 47.5' with same lens at same aperture. So if you needed to shoot a subject at 45', the 580EX would provide a suitable exposure, whereas the 430EX would result in an underexposed shot. Sometimes you cannot simply move closer.

Fill flash at -1EV outdoors in sunlight, and being able to do so (ISO 100 example) with f/11 from 16' rather than from 12' is another example, where proximity does not permit wide enough framing to fit everyone in the shot.

For me, the biggest issue is that the 430EXII does not permit external battery power.
That is a killer.

IMO if it doesn't take an external battery its not a flash that I want in my bag.

dmward wrote in post #14223358
For me, the biggest issue is that the 430EXII does not permit external battery power.
That is a killer.

IMO if it doesn't take an external battery its not a flash that I want in my bag.

And it cannot serve as a wireless Master unit. (But the OP questioned the need for power)

Wilt wrote in post #14223390
And it cannot serve as a wireless Master unit. (But the OP questioned the need for power)

True enough, but one aspect of power is recycle time.
Drop a 580 down the 1/2 stop to equal a 430, add an external battery and you have much faster recycle than with a 430 at full power with just the 4 internal batteries.

That was what I should have said in the previous post.