Recently we've gotten a couple of questions which essentially reduce to How many EV will a softbox knock down off your flash? — but that doesn't really have great answers. I know it's not a simple answer (like "add 2 EV and there you go"), but it'd be nice to have some discussion of flash GN and what might be appropriate for example situations. Will a mid-range ~ GN 30 flash ever be useful with a softbox, or is more power basically required when using lighting modifiers?

I'm happy to add a bounty to the above question, but I could also see a new question asking something like "How powerful a flash do I need for use with a softbox in typical situations?"

Which do you think is better?


1 Answer 1


Since it can vary so much from one light modifier to the next I'm not sure any such question is a good fit here unless a specific modifier is identified. It's kind of like asking, "How many horsepower does an engine need to accelerate a car from 0-60 mph in 6 seconds? Well, it depends on the weight of the car, the gearing in the drivetrain, the size of the tires, the aerodynamic coefficient of drag, etc.

  • \$\begingroup\$ Do you think it really needs to be a specific individual (well, line/model) of modifier, or would "medium-sized softbox designed for speedlight-style flashes" be close enough to give useful ballpark answers? (How many horsepower does it take for a typical four-door family sedan?) \$\endgroup\$
    – mattdm
    Commented Mar 1, 2017 at 10:44
  • \$\begingroup\$ There's still a pretty wide variation. And most softboxes have adjustable baffles that also affect how much light they eat. Does the car only contain a single driver or is it loaded down with four people and their luggage on the way for a two week vacation? The makers of most higher end softboxes will list a specification in stops of how much their product reduces the light in various orientations. The reason they do is because it is such a highly variable thing. \$\endgroup\$
    – Michael C
    Commented Mar 1, 2017 at 18:35

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