Digital photography is essentially a worthless activity without light. It’s the interaction of the light and the sensor that records the image, which means light is the most important concept of photography you must understand, and then be able to use, practically and successfully. An earlier PhotographyTalk.com article, Photography Tip—How To Mix Flash and Ambient Light for Better Photos, explains specifically how to combine these two light sources to create better images, using an interior setting as an example. This PhotographyTalk.com article expands on the ideas in the first article, but this time in an outdoor environment.

Achieving the correct mix of flash and ambient light begins by forgetting what you’ve learned about “fill flash.” If you have a TTL (through-the-lens) flash unit, then it generally sets itself automatically, in coordination with the camera. The first idea to forget is that you should leave the flash unit attached to your camera during “fill flash.” You may have taken the first step and already hold the flash unit off the camera and connected via a TTL cord. The problem is the common off-camera position is in the photographer’s left hand, causing every image to have a cast of light from that direction.

• Understanding Flash Photography: How to Shoot Great Photographs Using Electronic Flash
• Speedliter's Handbook: Learning to Craft Light with Canon Speedlites
• On-Camera Flash Techniques for Digital Wedding and Portrait Photography

Using your flash unit to supplement sunlight is a rather easy process.

• Select your camera's highest synch speed, so your small flash will be more versatile.
• Set your ISO at its lowest acceptable number for higher quality images and not to reveal CCD-chip dust spots.
• When shooting outdoors, consider the angle of the sunlight, not just the on-camera fill flash. On-camera fill flash typically creates more shadows as well as detail.
• Move the flash unit to a light stand, so you have two angles of light separate from the camera. Now you have more control of the depth and quality of two light sources and their many combinations.
• Next, consider your camera angle. For example, you choose a camera position, so the sun is behind you and to the left, and is hitting your subject or scene at approximately a 45-degree angle. The best place for your flash unit is not on-camera, but from the upper right. Now, think of the example above from the opposite side. Your subject is in profile, facing right, with the angle of the sunlight just behind his face to create an interesting rim light. Position your flash unit on a light stand to the left and raise it, to take a picture you couldn’t capture with the flash on-camera.
• Off-Camera Flash Techniques for Digital Photographers
• Sketching Light: An Illustrated Tour of the Possibilities of Flash
• Kevin Kubotas Lighting Notebook: 101 Lighting Styles and Setups for Digital Photographers

The second technique is to mix flash and ambient light in an equal balance. You read the ambient light to set the exposure, and then use the flash to fill shadows and/or cast light from a different position.

• Again, select the highest synch speed (lowest aperture, or lens opening).
• Then, determine the ambient light’s exposure. For example, 1/250th at f/11 at ISO 200.
• Attach your flash unit to a light stand. Select approximately quarter to half power if you’re close to your subject. Increase it to half to full power if there is more distance between the camera and the subject.
• If the space you are lighting is small to moderate sized, then zoom the flash to a 70mm to 85mm lens angle.
• Take a few test images and review them carefully. If there is too much light on the subject, then choose a lower synch speed or move the flash further from the subject. Do the opposite if there is not enough light: a higher synch speed and move the camera closer to the subject.

Recommended Reading:

• Master Lighting Guide for Portrait Photographers
• 500 Poses for Photographing Women
• 500 Poses for Photographing Men
• Light It, Shoot It, Retouch It: Learn Step by Step How to Go from Empty Studio to Finished Image
• Secrets of Great Portrait Photography: Photographs of the Famous and Infamous
• Shooting in Sh*tty Light: The Top Ten Worst Photography Lighting Situations and How to Conquer Them

This technique is easy and fast to execute: You don’t need a flash meter and you’ll maintain complete manual control, so the results are your best.

These techniques are just the beginning. There are many other balanced combinations of flash and ambient light to discover inside and outside, so don’t limit yourself and you won’t limit how much you’ll improve your digital photography.

PhotographyTalk thanks the folks with www.BetterFamilyPhotos.com for use of this photo! To get more information on balancing your flash with ambient light here's more on the subject: http://betterfamilyphotos.blogspot.com/2010/05/balancing-flash-and-ambient-part-2.html