Post & Photo by Joe Farace – Follow Joe on Twitter

There’s much confusion about studio lighting. Some photographers think it’s too complicated and expensive, but in reality it can be neither. Part of this misunderstanding is caused by bewildering array of product types and their accompanying buzzwords. Here’s a quick break down:

A monolight is a self-contained studio flash that consists of a power source and a flash head. This is all contained in a single housing. A monolight connects to your camera with a PC (Prontor-Computer, not computer) cable allowing it to be directly triggered from your SLR’s corresponding PC outlet.  Not all modern digital SLRs have a PC connection, but radio-controlled slaves, such as PocketWizards, allow a monolight to be wirelessly triggered without a cable. AC current typically powers a monolight, but there are times when you’re on location and an electrical outlet may not be conveniently located. A new breed of monolights, like Flashpoint’s 320M, offers a DC option that connects to battery power packs that are available from the company or third parties.

Watt-Seconds are a measurement of the power and discharge capacity of an electronic flash’s power supply (think automobile horsepower.) A Watt second of energy, equal to a Watt of power expended for a duration of one second.

Some monolights offer a Guide Number rating that is quoted in feet or meters (depending on where you live in the world.) Guide numbers are valid for a given ISO speed. The higher the guide number, the higher the light output. Guide numbers let you calculate an aperture when shooting without a flash meter. To determine the correct aperture, divide the guide number by the distance of the flash to the subject.

Other considerations when evaluating different monolights are flash duration and recycle time. Flash duration is what it sounds like…the amount of time elapsing after triggering the flash head. Recycle time is the time it takes after the flash has fired and until the monolight is fully charged and able to deliver a full amount of light for another exposure. This can vary between monolights and may be a determining factor in selecting one monolight over another. Until the flash recycles, you have to wait…

Many monolights have fixed power settings of quarter, half, three-quarters and full but sometimes you need more control. Having the output be continuously variable allows you to fine tune the exposure to get precisely the aperture and depth-of-field that you want for an image. Less expensive monolights provide an on-off modeling light to give you some idea of what the final lighting effect will be but those with proportional settings allow the modeling light to vary with flash output. Placing the modeling light, power supply, and flash tube inside a single housing creates heat so a fan-cooled monolight is better than an air-cooled model but will make the monolight bigger, heavier, and noisier, and more expensive. These are all the kinds of things you should think abut when shopping for a monolight.

To many photographers the ability to have the power supply and light head in a single package makes for simple set up and greater flexibility and that’s why companies offer packages consisting of monolights, umbrellas, light stands, and even a case for a single ready-to-go package.

Joe Farace is the author of “Studio Lighting Anywhere” the second book in a trilogy from Amherst Media. It’s available on

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  1. […] Good summation by Joe Farace over at PhotoFocus on the basic elements of studio flash units. Nice primer if you’ve never touched one of these things before. ‹ Previous Post Are YOU Backed Up? […]

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