Nikon flashgun output in watts?

[Rob_p]

Does anyone know what the flash output of a Nikon SB700 is in watts?

I currently use two flashguns with a mix of two studio heads for product photography. The flashguns are great as they have a very low output when needed, 1/128 vs 1/64 of the SB600.

The studio heads I'm using are almost too powerful and even on their lowest setting are still way more powerful than the flashguns. For doing shallow depth of field shots with studio flash you obviously need a very low power output but the studio heads I'm using are still too bright.

I'm looking to replace the set up with something like this from Elinchrom. As you can see in the spec list it says the power output is 25ws - 400ws. What does that equate to in flashgun power?

Any ideas?

 

[Garry Edwards]

It's difficult to say. Hotshoe flashguns have highly polished reflectors that make the most of (exaggerate)? the actual power, and then have zoom reflectors that produce impressive guide numbers.

But my guess, and it's nothing more than a guess, is that the flash energy is going to be around 60j and the equivalent output is going to be almost twice that.

 

[HoppyUK]

Does anyone know what the flash output of a Nikon SB700 is in watts?

I currently use two flashguns with a mix of two studio heads for product photography. The flashguns are great as they have a very low output when needed, 1/128 vs 1/64 of the SB600.

The studio heads I'm using are almost too powerful and even on their lowest setting are still way more powerful than the flashguns. For doing shallow depth of field shots with studio flash you obviously need a very low power output but the studio heads I'm using are still too bright.

I'm looking to replace the set up with something like this from Elinchrom. As you can see in the spec list it says the power output is 25ws - 400ws. What does that equate to in flashgun power?

Any ideas?

As it happens, I have tested the Elinchrom D-Lite 4, along with a couple of dozen other studio heads and some big hot-shoe guns, all in the same light modifier at the same distance. The modifier in question is a Lastolite Umbrellabox, which is a reverse-firing white umbrella with a softbox front, so all the light is collected, scrambled and projected in exactly the same way, as far as is reasonably possible, and it can also be fitted to any head.

Trying to get a Ws equivalent is difficult, if only because Ws is a measure of energy stored in the capacitors and that doesn't always translate to how much light comes out of the front. In other words, there's no fixed starting point.

But if you assume that the D-Lite 400 puts out around the same amount of light as a typical 400Ws head, and I'd say it does, then that makes a Nissin Di866 around 100Ws, Canon 580EX maybe a smidge more, and the meaty Nikon SB900 getting on for 130-150Ws equivalent.

I don't know how the SB700 compares off hand, though a careful conversion of guide numbers with the SB900 should get you close if you take the zoom head setting properly into account, ie compare like for like focal length settings. I'd guess that Garry's estimate is probably about right.

If you want low power from a studio head, bear in mind that the D-Lite 4 only turns down 3.5 stops from max (not the claimed five stops, which is an actual difference of four). You may be better off with a D-Lite 2, or even the new D-Lite One.

 

[Rob_p]

Ok thanks for the replies so far.

It's the low end power I'm looking at rather than the high end. Good suggestion on the D-lite one's rather than the fours. Looking at them, the power ranges from 10ws to 100ws which sounds more like it. However it says the power in Joules is 100, I thought an SB600 was called that because it has 600 Joules of power?

D lite one

 

[HoppyUK]

Ok thanks for the replies so far.

It's the low end power I'm looking at rather than the high end. Good suggestion on the D-lite one's rather than the fours. Looking at them, the power ranges from 10ws to 100ws which sounds more like it. However it says the power in Joules is 100, I thought an SB600 was called that because it has 600 Joules of power?

D lite one

Flash power is a can of worms. The two measures commonly used, Watt-seconds (Ws) or Joules (J, same thing) and guide numbers are both fundamentally flawed, hard to compare on paper and manufacturers are prone to, well, tell porkies.

The only way to really compare is to test and measure them side by side in a modifier that collects all the light and projects it in exactly the same way, and that very rarely happens. TBH I don't know anyone that has more reliable data on that than I do

But having done that, my general experience is that Ws is not a bad guide, though there are exceptions. For example, Elinchrom makes two types of head, the regular S-type that broadly lives up to the Ws claims, and the much shorter duration A-heads that are about half a stop down at the same Ws, but that's not set in stone either.

Some hot-shoe gun manufacturers put the guide number into the model name, but not all. Eg Canon 580EX has a max GN of 58, and the smaller 430EX is GN43. That's a difference of roughly 2/3rds of a stop - multiplying by 1.4 is a doubling of brightness. But guide numbers are notoriously unreliable as so much depends on the zoom head setting, or the reflector used.

As a comment, studio flash manufacturers tend to understate the power of hot-shoe guns, to make their products appear superior, in the confident knowledge that it's hard for them to get pulled up on it. They miss the point: you don't need big power with today's high ISOs, but fast recycle times and a modelling light are invaluable for portraiture. Claims of 50Ws for hot-shoe guns get bandied about, but the biggest ones are much more powerful than that. If you take 100Ws equiv for the biggest Canon/Nikon/Nissin/Metz as a rule of thumb, you won't be far out.