Yes, If you have it use it. I had a 270EX before I bought the sb700's and it worked in 1/1 manual (270 is like the 400).

The only possible problem would be currents when mounted on body. You might want to check the differences.

You may even be able to fire it with CLS. Off camera there is no danger of shorting it or your camera, so it may be a good way to go. Try all of the different channels and see if it is affected by the settings of the master (assuming you don't have a D3).

It will definitely be fine with a pocket wizard (a good excuse to buy some)although you will only be able to use it in manual.

I almost always use my flashes in manual, you will not be limited by not being able to use TTL.

Like putting a Nissan engine in a Ferrari

I see—thanks jonny. Do you think it would be a big problem if I set the flash to 50mm but used 35mm on the camera instead? Would I get something like a vignette?

Leaving the zoom at a low setting should work fine. If you ever find you need more light on a tighter crop you can always adjust the zoom then. At any focal length above 24 you'll be wasting a bit of power by lighting up things not in the frame. But that will just make the battery drain a bit faster, which may not be an issue for you.

Hmmm...everything seems to be working fine in full manual. Otherwise nothing works. I think in ETTL or whatever-it-is mode it fires at full power. I read the manual, and there is no AA mode. Wireless does not seem to work at all, not surprisingly. No high-speed sync or rear-curtain sync either.

The only thing I find a nuisance is that I have to constantly set the zoom on the flash manually. Would it be OK if I left it at 24mm and did whatever I wanted with my lens? Or is it important that they always match?

Otherwise I think this replaces my much-hated SB-400. It's more powerful, has vertical bounce, easier access to manual control, etc. I'd still opt for an SB-600 though any day.

Yeah, it should work, but I don't know anything about it.

I used an SB-28DX on my D300 before I got my SB-600. Manual worked, but it also had AA (aperture auto?) mode—you enter the aperture on the flash and the it has an on-flash meter that fires the flash until it gets the right amount of light (usually). Not as good as TTL, but it worked. Does the Canon have anything like that?

Ive heard that its a bad idea to use a canon flash on a Nikon camera and the other way around, the canon will try to break the Nikon with all its might! - ok kidding aside, but ive heard of things going bad,id suggest googling it a lot and read on it, not to say that it cant work in full manual, but its only going to be like that, no TTL etc. action.

I've been very busy lately (and still am). Lots of things I need to do, as well as spending time with my family and shooting as well.

Anyway, I found a moment to ask this question:

My dad has an unused (When I say unused, I really mean unused. I think he took one test shot with it, and that was it!) Canon SpeedLite 430EXII. It's miles better than my SB400. Has anyone ever used a Canon flash on a Nikon? I have to switch both the camera and flash to full manual for it to work properly, but I have liked the results a lot. Nothing else works at all, no wireless, no high-speed sync, but still. Any reccomendations/tips?