October 8, 2011: I photographed Renae and Brad's wedding this weekend. This was probably the most fun I've had behind the camera in a long, long, time. With so many wonderful people, photographing was truly a pleasure. I wish them both the very best, and am thankful that they included me in the celebration.
Shadows and Highlights: This kind of image is a photographer's nightmare. The sun's position was behind the guests The trees surrounding the venue rob the image of precious light. If you look at the wedding party standing by the arbor, you can see that for all intents and purposes, there isn't any light on their faces. The only option is to bring your own light into the photo. An on-camera SB-900 did the trick here. I was using a D7000 with a Tokina 11-17mm lens. The camera settings included a shutter speed of 1/125 of a second, an aperture, of F/13, an ISO of 200, and the lens' focal length set to 14mm. I basically established focus and walked, backwards, as the left the arbor. I used a wide angle lens so I could get as close to the couple as possible. Your on-camera flash isn't that powerful when it comes to equalizing the light of the sun. Don't forget to watch for perspective distortion when working this close. I tried to keep the camera as level as possible for this very reason.
Dragging the Shutter: Dragging the shutter is a term used to describe the selection of a shutter speed slow enough to record the ambient light that illuminates the background.
The photo was shot with the aforementioned Nikon D7000/Tokina combination set to1/60 of a second, F/4.0, ISO 3200. The long exposure and high ISO allowed the twilight horizon to add an interesting background. The camera-mounted SB-800 was already dialed back to 1/128th power and it was still overexposing the subjects even with the diffusion dome on (this reduces the output by at least 1 stop). To cut the power further, I removed a strip of gaffer tape (I always keep some small pieces attached to the side of the flash for holding gels in place) and placed it over the diffuser to cut the light even further. This did the trick.
I love digital, because it allows you to determine the background exposure settings using the "shoot and chimp" method. The shutter/aperture combination gave results that look good to me. The flash, used manually in this photo, could be dialed up or down, depending on the distance. I tend to establish the correct flash exposure for a specific distance and make it a point to shoot from there.
On Camera Flash? Well yes, considering that I was alone and it would have been very difficult to accurately direct an off-camera light source while scrambling for a good shooting position. The down side of on-camera flash is the placement of the specular highlight on your subject (think shiny spot on the tip of the nose). The light placement is unfortunately close to the lens axis, so the light goes straight out, and the glare reflects straight back. If you think of the human face as a sphere, the glare spot will be centered on the orb's surface. If you can move the light source well away from the lens axis, the specular highlight moves closer to the edge of the face, producing less glare overall. Try to think of your flash bracket as a way to eliminate red-eye and not as a great alternative to off-camera flash.
Glare and Distance: The lower photo shows much better glare control because I was standing very close to my subjects. The distance between the SB-900's flash tube and the lens axis is about 8 inches. My twilight shot was taken at a distance of about 3 feet. If I am to achieve the same effect at twice the distance, the flash should now be 16 inches above the axis . In the shot at the top of this post, I would have had to raise my flash well above my head to get the same effect.
Remember, this only applies when the flash is the primary light source for the photo. It is the exact opposite when the flash is used to add detail, or "fill" the shadows. Then you want the flash as close to the lens axis as possible to prevent double shadows.
