Nikon D800 and flash

[Sim TM]

<p>Hi,<br>

Back in the film days I had bought a Sunpak 4500 off camera flash, which I never sold. I tried it out using a sunpak slave and worked well with the D800's flash on manual mode.<br>

I wish to try it using the PC socket instead of the slave, would there be any problems in terms of camera circuitry or other.</p>

<p>Thanks in advance.<br>

Simon.</p>

[jim_momary]

<p>Recent discussions refer to here, but the 4500 isn't listed.<br>

<a href="http://www.botzilla.com/photo/strobeVolts.html">http://www.botzilla.com/photo/strobeVolts.html</a><br>

Jim<br>

(Some 4000, 4205 and 5000 seem safe, but no idea on 4500 really.)</p>

[bob_sunley]

<p>An inexpensive voltmeter will give you the trigger voltage, btw, the Auto 455 is the US name/version of the G4500.</p>

[dan_brown4]

<p>You'll be fine with that combination.</p>

[Sim TM]

<p>Thanks everyone for your advice.<br>

Simon</p>

<p> </p>

[rodeo_joe1]

<p>Beware of measuring the trigger voltage of a flash with an "inexpensive" voltmeter. Some cheap multimeters have a fairly low input resistance that can give a completely false reading from the high-impedance trigger circuit of a flash. Even a reasonably good digital meter with a 10 Megohm input impedance can be out by nearly 50% when measuring some flash circuits. That's why the reported trigger voltages on the Botzilla.com list vary so widely. Always take the highest reported voltage and then add at least another 10% for safety. Also, you will get a "tickle" if you poke a multimeter probe onto the P-C plug of an old flash with bare fingers!</p>

<p>Having said that, the Sunpak G4500 supposedly has a very low trigger voltage of around 7 volts, and the D800 - like all Nikon DSLRs - will withstand up to 250v on its P-C socket. In other words it should be safe to use, but if you have a decent multimeter, then check for yourself.</p>

<p>If anyone's interested in why a cheap low resistance meter gives false readings; it's because most "old" trigger circuits have a resistance of several Megohms in series with the trigger lead. Putting a meter resistance in series with the flash's internal current-limiting resistor results in a potential divider action, and only a portion of the true trigger voltage is read by the meter. Unfortunately it's voltage, not current, that causes breakdown of electronic components like the camera's firing thyristor or triac. So even though the current is severely limited, an old flash with a trigger potential of around 350 volts can easily kill a modern DSLR's firing circuit.</p>