|The PocketWizard AC3 ZoneController|
TTL stands for "Through The Lens" and means that the camera controls the power of the flash based on how much light it sees "through the lens". The problem is that TTL was designed with ON-camera flash in mind. The whole point of using a set of PocketWizards is to get the flash OFF the camera for better results. For example, you might want to put the flash behind your subject, to rim-light her as show in the photo below:
(That's Becca by-the-way. She a high-school senior whose portraits I shot this past weekend.) In Becca's case, I don't want to use TTL. Instead I wanted full control over the power of the flash, so I shot this image in manual mode.
Fortunately, you can also use the new PocketWizards to trigger a flash in manual mode. In manual mode, you control your flash's power using the knobs and buttons on the back of the flash. The problem with manual mode is that once you have a flash all setup--either high on a light stand or clamped to some out-of-the-way tree limb--it's often hard to reach, which makes adjusting the power difficult and time consuming.
Enter the AC3: Using the AC3 you can remotely control the power output--from full power down to 1/64 power--of multiple flashes assigned to one of three "zones". You can also turn off any zone, and set any zone to TTL mode, right from the comfort of your camera. Case in point: While shooting Becca's photo I was able to quickly adjust the power of the off-camera flash to give her hair just the amount of highlight I wanted. Sweet.
I found the AC3 extreamly easy to use, and at $70 it's a no-brainer for the type of photography I like to do (on-location portraiture using natural light and small off-camera flashes). Of course you first have to stomach the price of the MiniTT1 and FlexTT5s. If you get that far, might as well add the AC3 for good measure ... and more control.
I love shooting senior portraits. If you're a high school senior, or the parent of one, give me a call at 512-924-8256 or send me an e-mail, and I'll fill you in on all the details.