Can you use the same flash for both cameras?

I have a Nikon D3000 and A Canon AE-1 film camera. I have a flash for the Canon but I was wondering if you could use the same flash for both cameras?

If it connects properly, then I guess so, otherwise you'll probably have to invest in another one, or find some sort of adapter, but it's unlikely there's one.

The answer is maybe. Depends on what flash you have for the Canon. If it is a Canon dedicated flash, then no. If it is a generic flash with single center pin contact, the answer is yes.

It sounds like it would. Try it on the Nikon and see if it works.

Apart from the basic manual central connection, the other connectors are different on Canon and Nikon cameras. If it is a flash made by Canon then it will probably not work. If it is a third party flash then maybe it will work, if it is basic or if it has connectors for multiple brands.

Even if it does work, you certainly won't get i-ttl flash and will probably have to set the flash settings manually. It is easy to get the exposure wrong with manual or even semi-automatic flash.

You would be better off buying a Nikon Speedlight SB-400 for the Nikon which will give you proper TTL (through the lens) flash metering.
http://www.amazon.co.uk/...000KKPN5C/
The sb-400 is small and lightweight, so easy to carry around, but it's still a pretty good flash and will be easy to use.

The flash for the old Canon will not work in TTL mode with the Nikon. It might work with the Nikon in manual mode. Familiarize yourself with x-sync speed and guide numbers.
BUT, there's another issue. Old flashes that could work fine with film cameras often have trigger voltages that can fry a digital camera's electronics. Check here to see if your model is safe to use with a DSLR:
http://www.botzilla.com/photo/strobeVolts.html
Better yet, get a Nikon Speedight and have something that just works.

The flash will fit both cameras. You can use the flash in Auto or manual mode with both cameras in manual mode. Check voltage requirements though. Some flashes have been known to burn some digital flash shoes.

As already mentioned… The biggest concern is the flash trigger voltage.

Some flashes can easily do 170+volts, and most DSLRs can only handle 6-12 volts. IF you insist on using an older flash flash on a DSLR, I would recommend using a "safe-sync" until the flash voltage can be determined… Http://www.bhphotovideo.com/c/product/245292-REG/Wein_W990560_Safe_Sync_Hot_Shoe_to.html