How to Use a Single Flash Unit for Portraits

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One camera, one lens, and one flash—if you've got these you can create compelling portraits. Some important things you must be familiar with in order to achieve ideal illumination of your subject: bouncing your flash, flash modifiers, F-stops, shutter speeds and ISOs.

Bouncing Your Flash's Output

One of the reasons why so many people become annoyed with their flashes is because they don't know how to use them. Many people point their flash head towards their subject, and expect to get professional-looking results. Nothing could be further from the truth.

One of the best ways to illuminate with a flash is to bounce the light output off of something else, in effect turning it into a giant reflective surface. This method is commonly used for portraiture, event photography, weddings, concert photography, etc. The important factor is to pay attention to the angle of the surface off which you are bouncing the flash.

Here's an example to illustrate:

This is the effect you get when the flash is bounced straight up at a flat surface. Notice the shadows under her eyes and chin.

When you aim your flash head up and to the right, the light hits your subject from a different angle. The offending shadows are gone. Take a look at her neck. Notice how her left side is more illuminated than her right.

And this is what happens when you bounce the flash up and to the left. Observe how the right portion of her face is brighter than the left, as a result of the illumination.

Wireless Flash Control

The first thing you should know is that your flash can be used out of the hot-shoe, controlled wirelessly by your camera. Using wireless flash control, you can:

  • Have the pop-up flash trigger the external flash
  • Tell the pair to work together to expose the image
  • Have them work together in a ratio

Photo by josephjulian

The point of wireless flash control is not only to take the flash off the camera, but also to help add dimension to your photos through the shadows. You can see an example of this in the photo above. Since it is so small, your flash can be placed almost anywhere. This allows you to have tremendous versatility when shooting, especially when you combine this with the use of flash modifiers.

Flash Modifiers

I've geeked out a bit about flash modifiers before, and I know that I've said that flash modifiers will change your life—but seriously; flash modifiers will change your life. They come in many different shapes, each tailored to accomplish a specific task.

For those wondering what flash modifiers are, they are special accessories that go over your flash's head, and modify the light output based on their specific shape and size. Here are a couple of popular ones:

Gary Fong Collapsible - Modifies your flash output to have a bare-bulb look. It's best used for vertical photos, and can deliver great results when used off-camera with wireless flash control.

Impact Strobros Beauty Dish - Makes the flash output look similar to that of a small but powerful softbox. It can be modified by changing the disk used for bouncing the flash. In my tests, it is best used with long lenses.

Orbis - A ring flash attachment with a large surface area that also warms the lighting. Because of the design, it is best used with a TTL cord, unless you choose to use it as a softbox.

ExpoImaging Ray Flash - Another ring flash attachment that delivers lighting results that look very natural. It is best used around the lens, with your flash mounted into the hot shoe.

ExpoImaging Rogue Flash Benders - Think of these as bounce cards that are extremely flexible and can be molded into almost any shape you can think of. In all honesty, you can mount these onto your flash and put the flash anywhere you want, depending on the look you're going for.

Harbor Digital Lightbox Diffuser - Similar to the Gary Fong Collapsible, but with a white card, to utilize all output from the flash.

Reflectors

Reflectors are extremely helpful with manipulating the light in an image. There are different ways to use them:

- Place a flash unit aimed at one side of the subject and the reflector on the opposite side. When the flash goes off, the reflector will bounce the flash output, and even out the lighting. This must be done with a transparent reflector.

Alternatively, if you set the reflector up on a stand, you can substitute it for an umbrella.

- Aim the flash through a transparent reflector to soften the flash's output. This will give off the effect of a large softbox.

Don't want to have a bunch of reflectors? Try the Impact 5-in-1.

Your Lens

By changing the aperture, your lens can control the flash exposure projected onto an image; the narrower the aperture (F/11), the lower the exposure, the wider the aperture (F/1.4), the greater the exposure. Many photographers tend to shoot portraits with their apertures set anywhere from F/4 to F/11, not only to control the flash but also because these F-stops allow them to have exactly what they want in focus.

Exposures

There are other variables of exposure that will control different aspects of your final image.

Shutter Speed - Controls how much ambient light is in the image. The slower the shutter speed, the more ambient light will seep into the image. The faster the shutter speed, the less ambient light will come in. Shoot at too fast a shutter speed, and your background may go into darkness.

ISO - Controls the light sensitivity. Raise your ISO, and the flash output and ambient light will be intensified at a given shutter speed and aperture; lower it, and you'll see the exposure become darker. Oftentimes, photographers shoot between 100-400 ISO outdoors, and 800 to 1000 indoors. Personally, I've gone all the way up to 3200.

Exposure Compensation on your flash - Controls the power of the flash's intensity. When shooting in manual mode, many photographers tend to leave the flash output at 1/1 so that there is one less variable to worry about. This is a very powerful flash output, so these photographers also tend to work with the other variables (shutter speed, aperture and ISO) to get the image that they're going for.

Professionals: What ways do you use a single speedlight for portraits?

Hobbyists/Amateurs/Enthusiasts: Was this helpful?

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That was very informative and helpful, thank you.

Absolutely useful information.