After a long time SB-900 released, Nikon upgraded it to SB-910, a more powerful speedlight.
The major improvement of SB-910 focus on operation. And it also improved over-heat protection function. By monitor flashlamp and body temperature, the SB-910 will down the current to avoid shutdown.
Besides, SB-910 have 3 flash model which are standard model, average model and center model. It can also auto detect DX/FX to optimize picture quality for different models. SB-910 will be shipped two weeks later for a price of $549.