Pocket Wizards are a professional photographer's best friend. They are small, affordable, and allow the photographer to remotely set off flashes from anywhere in the room. Off-camera flash is the one thing professional photographers have that amateurs don't. Having your light source hit your subject from a different angle will make the subject and light look more natural than a light hitting them straight on.
Say goodbye to red-eye. Pocket Wizards are the easiest way to learn the hardest thing about photography: lighting.
Pocket Wizards have two parts, a transmitter and receiver.
The transmitter goes on your camera and usually connects through the hot shoe and transmits a signal to receivers on the same channel every time you release the shutter. When your flash is connected to a receiver it will go off every time it gets a signal from the transmitter; so every time your shutter triggers, the flash will go off at the same time. It should be that fast. The remotes can have up to 52 channels so make sure you are shooting on one that no other photographer is also on. The transmitter has an 800 foot range so if you are working around a lot of photographers it's not uncommon to accidentally be on the same channel. This also means you can have multiple flashes on multiple receivers go off at the same time, as long as they are on the same channel.
How can you use Pocket Wizards?
You can find a set online for about $300, which in the camera gear business is pretty inexpensive. Especially for the return you will get from them. I use my Pocket Wizards on almost every shoot. They connect to studio flashes as well as my Speedlights. You can use them indoors and outdoors. When shooting outdoors, having a light on a subject allows you to shoot in all different kinds of lighting conditions. All you need is a flash, light stand, mount, and your pocket wizards. Now you have a traveling studio. You can bring a smaller studio when shooting smaller groups or a single subject, like senior portraits or bring the whole kit and kaboodle to larger events like weddings. The Pocket Wizards will make both easier to use.
Your flash isn't talking directly to your camera anymore, since you took it off the hot shoe, you can't use TTL anymore. Switch your flash to manual, and figure out how to turn it down from full power to about 1/4 or less. The decreased light coming from the flash will make your subjects happy and it won't take as long for you flash to charge back up. Then, play with where to position your lights. Don't be afraid to be creative or use dramatic lighting. With Pocket Wizards you can put a flash anywhere, within 800 feet. Once I strapped a flash to a pole so I could have a second light out of the way while photographing a fashion show.
What types of photos can I take?
Every time you see a wedding sunset portrait with the sun in the background and the couple beautifully lit from the side, Pocket Wizards were probably used. Sports photographers who shoot indoor sports like basketball hang huge strobes along the catwalks of the arenas and use Pocket Wizards to set them off during the game. Most high end real estate photographs have lights coming in from different directions to make a home look brighter than it really is. Next time you see a photo you really like, take a second look and see if there was some extra lighting used. If so, they probably had some Pocket Wizards.