Dual 580EXII's vs Quadra?

.mark. wrote in post #15461849
Thanks for the reply. So do you agree with the blog I quoted in the first post that the quadra is 1 1/3 stops more powerful than a 580EXII? I'm finding it hard to justify spending over £1000 to get a single quadra and pack, when if I can get pretty much the same power output using a dual speedlite bracket.

80ws to 400ws ... wouldn't that be 80x2=160 1 stop.... 160x2=320 a 2nd stop... 320x2=640, so about 1/3 additional. Wouldn't the Quadra be 2 1/3 stops better, so you'd need 4 x 580s to get to 2 stops, and another 2 probably to get the other 1/3... so 6 x 580X to equal the same ws. But of course, there is way more to light than just that.

Trailboy wrote in post #15462135
Are two cheese sandwiches better than one ham sandwich?

You are not comparing like with like, so stop trying.

They are fundamentally different and essentially incomparable.

I have several 580exII and a Quadra. If you knew why you wanted a quadra, and its benefits, then you would not "find it hard to justify spending over £1000....."

Wow... seems a bit harsh. Isn't this the place to ask questions???

Absolutely.

It wasn't meant harsh at all, tbh.

Light is Light but these are two different items
Thats like comparing a Lambo to a Dodge Viper. LOL

The Quadra can pop full power longer
The 580EXII will over heat trying to keep up with the quadra.

2x580 full power=160ws
1 quarda head full power is 400ws

you will need 5 580's to =400ws

LOL crap to slow at typing and answering the phone

My question is what modifier you using? Most you can put two speed lights in, but to put in 5 you need a special rig or modify the modifier.

Just in case someone tries to do some math, it's Ws that's the unit, nothing else.

If the 580 is 80ws, then that's with the head zoomed in to 105mm. At that setting are two of them going to evenly illuminate the front panel of your softbox? If not you you're going to have to zoom them back a bit, which equals less power. If you're planning on shooting full sun, I'd want more than 400ws.

Ws (wattsecond, which is the same as Joule) is a unit of energy. In this case the energy dissipated into the flash bulb. It makes no difference at all what zoom level the flash is set to - the energy is the same. It will cause the same light intensity (which is a measured in candela) at the source, the flash bulb.

What you are thinking of is the guide number, which is another way of describing the intensity of the flow of light coming from the flash. That's measured in lumen, which is candela x steradian, or source intensity multiplied with the angle the light covers. When this light reaches an object, it will illuminate the object, and this illumination is measured in lux, which in turn is defined as lumen/m².

A light that has an output of 400 Ws can be very weak (few candela), or very strong. It may be like a 1 W lamp, if the flash in on for 400 s, or a 40 W lamp if it's on for 10 s. But in reality it's on for a fraction of a second, and thus corresponds to a lamp of far more than 400 W power.

One could use the same nomenclature for a Speedlight, but since the guide number is convenient when the flash is on the camera, and flash guns are more commonly mounted on the camera, compared to a studio strobe, I at least assume this is the reason for the different traditions for how to rate these light sources. A studio strobe can of course also be equipped with a reflector, in which case it will get a zoom setting similar to the flash guns. But usually we want to soften the light from the strobes, not concentrate it even further.

I have two new 600ex's with the STE3 and love them for off camera flash. I also have the 2 light Quadra system and have had it for a long time.

As stated above, there is a huge difference when placing the lights in a soft box, especially one of size. Just take a picture of the front of the box when it's popping and you'll see the blinkies on your camera right in the middle of a rectangular or even square box, forget about a strip. A speedlite will in no way give you even light across the box, even two.

Whereas the Quadra will light that box from edge to edge evenly.

Also, unless I missed it, the Quadra has a nice LED modeling light.

For portraits or critical applications when using a modifier, the Quadra beats it hands down.

Trailboy wrote in post #15462314
Vagabond mini is not a realistic option outside of the US.

OP is in the British Isles, like me.

There European Battery/Inverter options.

What it really comes down to if finding the best light for the job at hand.

Because I'm US based, I've found that Einsteins and VMLs are a reasonable solution for battery powered outdoor light.

I also have a lot of speedlites, which I tend to use for fast moving situations.

For me a major consideration is what modifiers.

apersson850 wrote in post #15465028
Ws (wattsecond, which is the same as Joule) is a unit of energy. In this case the energy dissipated into the flash bulb. It makes no difference at all what zoom level the flash is set to - the energy is the same. It will cause the same light intensity (which is a measured in candela) at the source, the flash bulb.

What you are thinking of is the guide number, which is another way of describing the intensity of the flow of light coming from the flash. That's measured in lumen, which is candela x steradian, or source intensity multiplied with the angle the light covers. When this light reaches an object, it will illuminate the object, and this illumination is measured in lux, which in turn is defined as lumen/m².

A light that has an output of 400 Ws can be very weak (few candela), or very strong. It may be like a 1 W lamp, if the flash in on for 400 s, or a 40 W lamp if it's on for 10 s. But in reality it's on for a fraction of a second, and thus corresponds to a lamp of far more than 400 W power.

One could use the same nomenclature for a Speedlight, but since the guide number is convenient when the flash is on the camera, and flash guns are more commonly mounted on the camera, compared to a studio strobe, I at least assume this is the reason for the different traditions for how to rate these light sources. A studio strobe can of course also be equipped with a reflector, in which case it will get a zoom setting similar to the flash guns. But usually we want to soften the light from the strobes, not concentrate it even further.

What I'm actually thinking of is effective watt seconds since we're talking about two different types of lights.....it's a way to relay results to someone without them knowing the difference between a watt, a watt second, or guide number. This was the only way I could learn before I was able to grasp the concept. I was trying to speak in a way people will relate....maybe I failed.

Anywho, here's a good article where David Hobby covers things you need to know about ganging lights together.

http://strobist.blogsp​ot.com …e-way-heres-what-you.html


You'd need six to equal what the Quadra could do and be limited to the modifiers that the flash could effectively fill. 6 hotshoe flashes will be about the same size and weight as a 400ws monolight, recycle slower and won't be able to stand rigorous use. If the 580 can be had for $300, then that's $1800 worth of strobes, maybe $100 to $150 in rechargeable batteries to have enough power for a long shoot, a means to trigger them all, and a specialty bracket. The costs add up......if the difference is indeed 2 and a half stops.

If you're going to want to work in the sun with 400ws, you're going to need an efficient modifier, or have your modifier in close. I've used an extreme silver PLM on a AB400 and was able to work in sun any hour of the day.

So now you know some of the obstacles you're up against. I'm not saying one is better, it's all about what you want.

I understand very well how you were thinking. I just feared that somebody else was perhaps confused, and tried to define a few terms. The fact that Ws is written in different (wrong) ways by different posters doesn't make it any easier to follow.

Changing setting during the shot is a lot easyer on 1 quadra then 2 or even 4 580's
and as mention before, the quality of light is a big different to!!

apersson850 wrote in post #15469400
I understand very well how you were thinking. I just feared that somebody else was perhaps confused, and tried to define a few terms. The fact that Ws is written in different (wrong) ways by different posters doesn't make it any easier to follow.

Ws, ws, w•s and w/s (with capitalisation as appropriate to correct sentence structure) are all acceptable abbreviations of the term depending on:-
1) the variant of English used (there are over 40 identified and accepted variations in use across the world)
and
2) the era in which you first learnt/learned the term.
I'd certainly agree though that it would make for easier reading if things were standardised (or is that standardized?), especially for those whose first language is other than English and who may lose subte nuances courtesy of an on-line translator.

dmward wrote in post #15468637
There (are) European Battery/Inverter options.

Because I'm US based, I've found that Einsteins and VMLs are a reasonable solution for battery powered outdoor light.

There certainly are options, but the readily available ones tend to be variants of US-made models. By the time we get them, they are very pricey indeed. A combination of shipping costs, duties and taxes and (in some cases) sheer greed. Often the support is fairly poor too, PCB faring especially badly in this respect according to various reports from across Europe.

Other routes can be found, but they do require a little more research than many are prepared to put in. You know how folks want stuff handed to them with no effort on their part!

Whortleberry wrote in post #15469584
There certainly are options, but the readily available ones tend to be variants of US-made models. By the time we get them, they are very pricey indeed. A combination of shipping costs, duties and taxes and (in some cases) sheer greed. Often the support is fairly poor too, PCB faring especially badly in this respect according to various reports from across Europe.

Other routes can be found, but they do require a little more research than many are prepared to put in. You know how folks want stuff handed to them with no effort on their part!

I was thinking about Innovatronix, which on closer examination I discovered is a Philippines based company. For some reason I thought they were German or Swiss.

Buffs "problem" is that adding layers of distribution breaks his pricing model. It happens all the time when a US, or even EU company tries to distribute into another area of the globe. Political interests add a layer of cost as well. Regardless of which direction the material is flowing.