While you may be able to use your diffusers/bounce,etc on the new flash, like 7ender said, It looks like to use this flash, it isn't looking very backwards compatable. It said it can trigger, but only to 600 series "slaves"... so yeah... I guess that's the price we pay for new technology. Kinda bummed the new 5d3 doesn't have any commander of any type or fashion, but we did get a new $800 wireless trigger... I guess that counts.