How To Buy A Flash System
by William Lulow
Today, photographers don’t need the kind of light output that they used to in the days of film. As I have said many times, the sensors in modern digital cameras are far more sensitive to light than film is. So, we just don’t need the same kind of power from our studio flash systems any more. But, sometimes we need more than we can get from a small speedlight. To give some kind of an idea of the power difference, 100 watt seconds of light is roughly 10 times the power you would get from a small speedlight.
Here are some quality studio flash units:
These power packs have light output ranges from 1000 watt seconds to 2400 watt seconds. The more light your unit can churn out, the smaller the f/stops you can use and thus, the greater depth of field afforded. These are also quite expensive – ranging in price from $900 to almost $4,000. These power packs store electricity from an outlet and release it through a flash tube when the shutter is tripped.
So, whenever you consider buying a piece of equipment like this, make sure that you actually have a use for it. Most portrait studios have smaller power packs that will allow their photographers to shoot with moderate f/stops and depth of field. Some of the more expensive ones are really designed for still life studios where shooting with very small lens openings is required.
The smaller speedlights are usually good for most uses that don’t require a lot of power. Speedlights can be bounced from ceilings, walls or reflectors. A decent speedlight power is probably a guide number of 130 or so. That should enable the photographer to do some portraits with an f/5.6 opening. The other problem with speedlights is that they have limited light modifiers that can be used with them. It’s difficult to rig up an umbrella, for example, with a speedlight. There are brackets made for the purpose, but I have found them to be rather cumbersome to use.
Speedlights are more portable and are designed to provide light for situations outside the studio. They are great for fill-in applications on location, for example and are best used on-camera with extra speedlights placed on light stands. They can often simulate lighting from studio flash units, but are not as powerful. They use batteries for power.
These are examples of some speedlights:
So, if you shoot weddings or events and need some good portable light, speedlights are the way to go. If you do mostly studio work and need to power several flash heads at the same time, then studio flash units are necessary. Just remember that the studio units are normally much heavier, take more power and are more expensive. Portable speedlights are lighter, run on batteries, give much less power and are less expensive.