So as mentioned above, I have a D90 and an SB600. I can set up the SB600 to be used as a flash on-camera and off using TTL w/ the D90 as a commander. What I'm trying to understand is can I fire the SB600 without using my on-camera flash as a trigger? Maybe I don't quite understand how CLS/TTL works, but I was thinking that I'd be able to put the SB600 wherever I'd like and could fire it wirelessly (there's also an AA setting that i'm not sure about). I know that Pocket Wizards and Cactus wireless triggers exist and I think I understand how they work, but I'm wondering if they're a requirement when you're using all nikon gear with a body that is a commander...
Thanks.