Nikon folks had the upper hand against other camera for many years with their Creative Lighting Systems (CLS). Using a nikon compatible body or flash to control other flahes through CLS and still be able to do iTTL is an awesome feature. That feature works great indoor or outdoor where there are direct light of sight. While limited, it did offer something other camera did not have and not needing to buy as an add-on. I had used it numerous time in the past and also used with the Nikon SU-800 commander as well.
Recently Pocket Wizard released their radio trigger version for Nikon systems with working TTL. This takes the ball game to a whole new level. Not only can you control other flashes in TTL mode, you do not need to have direct line of sight. It so easy to use and setup that it is simply as 1-2-3.
1) You will need a Pocket Wizard Mini TT1 or Flex TT5 for your camera (I used mini TT1).
2) You will need a Flex TT5 for off camera flash.
3) Connect, turn on your flash, leave it in TTL mode, turn on the Pocket Wizard to C1 (both on camera and on the flash), and start shooting
You can access more advance setting via USB port when plug to your computer. That also allows it to be flashed with the latest firmware when Pocket Wizard releases them.
Today, I had to pleasure to test out the pocket wizard with Marni. A young student who one day would love to be an actress. The pictures were taken outdoor around 8:30AM - 9:30AM out in the park.