Can you use the vivitar zoom thyristor 2500 with canon 10d?

Generally, as long as the camera has a standard "hot-shoe," everything should work. The 2500 appears to be for an older camera though (because it only has one contact on the bottom and it uses a synchronization cord) I wouldn't use it (see: http://en.wikipedia.org/wiki/Hot_shoe )

If you still have the need for a zoom thyristor, I would try to find the 3500 model from Vivitar. It has the standard three contacts on the bottom and would probably work..... However, with a high-end camera such as this; be careful about accessories you use because you could accidentally damage it. If you're still in doubt, ask your local dealer about it....Hope this helps.

~Cliff