I agree. Basically that tutorial tries to explain just how important power is (or isn't) in studio flash photography. I did think about going off at a bit of a tangent and mentioning hotshoe flashguns, but I decided against it
1. Because people tend to lose interest if tutorials are too long
2. I couldn't explain the complicated and misleading testing methods on hotshoe flashguns in just a few words...
F/number in a regular 100cm softbox would seem to me to be a) most relevant, and b) less prone to variables than current methods.
Agreed, but I can't see it happening. As you suggest, not all manufacturers may want their prospective customers to know the truth.
Heck, even a standard white 100cm brolly would be better than what we currently have.
Yes, an umbrella placed at whatever distance is needed to fill it to an agreed point would work perfectly but again, what chance is there of all manufacturers adopting a standard that may reduce their sales?
Ws is a universally
misunderstood criteria. I honestly believe that guide numbers, for all their faults, are more meaningful and more easily understood, simply because anyone should be able to replicate whatever figures have been claimed, and so they should be able to tell other people if the figures can't be achieved. Even so, there are still firms claiming guide numbers that are totally false, just as some of the colour temperature consistency figures claimed by some (usually the same) sellers are false - but they tend to get away with it.
FWIW, I think 200Ws is the most useful amount of power for most home studio set-ups. You can usually turn it down enough for f/2.8 at low ISO, and at full power with a couple of stops extra ISO it's enough for small groups with sufficient DoF.
That's exactly how I feel. Frankly I don't see the point of very high powered mono heads, which are pretty much limited to around 1500Ws anyway, they tend to cause more problems than they solve and I'm not even sure that there are any problems to solve.
In my experience the lighting situations that need a lot of power need a lot more than can be realistically engineered into a mono head; industrial photography is the province of mains powered generator units, not mono heads. I've often had to use a 6000Ws and 6 x 2400Ws generators in a large factory and have still been wanting more...
The point that I was really trying to get people thinking about in
that tutorial is this one
ISO speed is very important. Years ago when everyone was shooting on film, there was nothing much we could do about ISO speed – we could always change to a ‘faster’ film with a higher ISO speed, but doing this always produced a lot of grain, so we were pretty much limited to films of around 100 ISO.
And we had similar problems with the early digital cameras too. For example the Canon D30, the Nikon D100 and the Kodak DCS14 cameras were all capable of fine results at 100 ISO but the image quality fell apart at higher ISO settings. But now, with modern DSLR cameras, the results are pretty good at reasonably high (but not very high) ISO settings and pretty much every DSLR camera is capable of producing acceptable results at 400 ISO. So, if you move the ISO setting from 100 to 200 ISO you will effectively double the power of your flash head, and if you move it from 100 to 400 ISO you will effectively quadruple the power!
