Looking for Answers about Nikon Inc. SB-900 AF Speedlight?

Increase the iso on your camera. the more you rely on a flash to fill the room, you are putting strain on it. Set the iso to a value you find acceptable and go from there. Also do not use FP sync. on my current camera i have found a happy medium between an acceptable iso value and firing at 1-16th full power and have found overheating issues to go away and i can fire in pretty rapid succession using plain duracell batteries. (another advantage is you will not find yourself fumbling to change batteries as often)

I have experienced the problem when shooting fire performers. where shooting time is limited to the time the flames are alight for. You don't have to use the flash for that long before it goes, a couple of minutes (and that is with the flash shooting at -1. A lot depends on the batteries you use, from what I have read. I have heard all sorts of different advise on reasons why and what batteries work better or worse. Turning down the power of your flash and using multiple flashes is the easiest way to stop it. Shooting slower, allowing the heat to dissipate will help but is limiting. I am not going to say which batteries you should use or if you should use a battery pack as I have heard so many things.

The most recent firmware update for the SB-900 Speedlight is version 5.02 which was released in November of 2008. The "Update" date reflects a change to the web page while the "Published" date is the date of the firmware itself.

If the firmware on your SB-900 is older than version 5.02 then you can use your D800 to do the update. Any DSLR that shows the "S" firmware option when a speedlight is attached can be used to do a Speedlight firmware update.

Firmware version 5.02 can be downloaded from this address:
http://support.nikonusa.com/app/answers/detail/a_id/16174

You should be able to do it with the D800, just follow the instructions, I suspect the only reason the D800 is not showing is because the SB-900 has been discontinued and therefore the camera list will not be updated. Either that or find someone that uses one of the listed cameras and do it like that.

either that or you are using the d7k in a higher iso mode, since the d7k has eons better high iso than the d40. and higher iso->less need for light, so it's possible you're simply using your sb900 on a lower output.

They all overheat, the firmware update does not help. Different batteries does not help. The only things that helps is slowing down how fast you are shooting, turn up the ISO and shoot in brighter areas.......

Nikon staff, please admit to the problem and fix it. I have 10 of these sitting on the shelf at my studio not being used because we cannot not depend on them. If you can't or won't fix the problem, bring back the SB-800.....call it an SB-850 and charge $50 more than the cost of an SB-900 and I will buy 10 right away.

Or use the SB-900 in SU-4 mode and control it manually.

Yes it can.

Yes. Use it in the Remote function. There is a lot of great info online for Nikon's Creative Lighting System (CLS).