Flash Photography - The Importance of Power
By Bobby Jonnes

I’ve written this article so that you are clear about the importance of power in relation to flash. When I was just starting out, I asked a wedding photographer I knew what sort of flash I should buy. His answer? “The most powerful one you can afford”. This sounds too simplistic doesn’t it? I assure you, it was good advice then and it remains good advice now.

Powerful flashes can be turned down, or you can stop down your camera. Flashes without enough power limit your options. The lenses you can use in any given situation, the effectiveness of bounce flash, the distance you can be from a subject, even the flash duration, are all dependent on how powerful your flash unit is.

I’ve collected a variety of flashes over the years and all will provide useful light. One of the least powerful flashes I have, an old manual model, still sees regular use as a background fill light for some portraiture work.

A flash gun is too important a piece of equipment to skimp on though, and the versatility that comes with more power is irreplaceable. As fully featured as flash units have become, the thing that determines price the most is still the guide number.

For this reason, as I’ve already said, it is necessary to appraise your real need before you purchase anything.

If you are planning on doing wedding photography, you will be in large churches and halls and will need a flash that can light your subject adequately in those situations. If you are planning on photojournalism, you will require a unit that provides fast recycle times as well as enough power to be versatile.

By appraising your needs you can determine exactly what you need to buy. Pay attention not just to the guide number, but to the adjustments and features that are available. A flash that can deliver enough power in any situation is important, but the ability to control that power for the effect you want is just as important.

One of the best features for making full use of flash power is a zoom option on the flashgun.

Many flashes have a zoom feature. On many modern, dedicated flashguns this feature is internal and automatic, matching the lens you are using and what focal length it is zoomed to. Older flashes tend to have three or more settings that are manually set by the user. Basically these are wide angle, normal focal length and telephoto.

No matter whether you have a brand new flash with automatic, internal zoom or an older flash gun that has to be manually set, the goal is the same, to match the angle of flash coverage to the lens you are using.

My advice to you is to fully understand this simple concept. Even if you are using fully automatic units there may come a day when you have to set the zoom manually, it is then you need to understand it.

Now you know a little more about the importance of power in relation to your flashgun.

Do you want to learn more about how I do it? I have written a comprehensive guide on flash photography.

Download it free here Flash Photography Guide

Bobby is a photographer and author. He has been commissioned to shoot thousands of events, including weddings.