Recently I've got this flash, and after researching about it and Nikon's hotshoe voltage, one doubt has appeared. In the manual of several cameras, it's written that the maximum voltage of the hotshoe is 250v, is that correct? And does it apply to my DSLR?
Info: Vivitar 2800 voltage sits between 140/170 I guess.
From the D3100 user manual, page 172:
... Negative voltages or voltages over 250 V applied to the accessory shoe could not only prevent operation, but damage the sync circuitry of the camera or flash.
Given that this is the published information in the user manual, I'd say, that yes, the 250V limit applies to your camera, and as long as you know the measured sync voltage is within 0-250V, it should be safe.
