Don't Fry Your Camera
Such is the case here. I'd like to give credit for this one, but it was posted by "Anonymous," deep in the site's comments section. (Folks, please leave a name and fill in the website field, so we can see who ya are, K?)
Anyway, he (or she) posted a link to a cool website that lists the synch voltages of many, many strobes.
Why is this important? Well, as we talked about before, recently designed cameras handle the synching functions through the main circuit board. They used to do this with a mechanical contact point, which did not care about the synching voltage of the flash.
But they care now. Long and short of it is, some old flashes have synching voltages that will fry your new camera if hooked up directly, either on the hot-shoe or with a PC cord. They were simply made before anyone knew synch voltages would be an issue.
If you are using any kind of wireless setup, like the eBay thingies or Pocket Wizards, you are already safe.
The site gives good general info about camera synch voltages, and names names. Many modern cameras are similarly designed. So even if yours is not listed, this info should give you a pretty good ball-park estimate on whether or not your proposed flash/camera combo is safe.
The not-so-good news is that the site is apparently up and down occasionally. If it is on a bandwidth-limited free server, I am sure you guys will exceed the limit by a few orders of magnitude. So it may be tough to log on to it.
So, in case it is not up, I can tell you that the older flashes I have recommended here (Nikon SB-24, -25, -26, -28, -28dx, -50, 80, 800, etc.,) are well within the safe range.
But if you are using something else, be sure to check your flash to see if it is one of the naughty ones.
Thanks for the great tip, whoever you are!