Paul
On Dec 18, 2004, at 10:49 AM, Don Sanderson wrote:
Here are the isolators I'm refering to:
http://www.adorama.com/WNSSPC.html http://www.adorama.com/WNSSHSHS.html
Don
-----Original Message----- From: Don Sanderson [mailto:[EMAIL PROTECTED] Sent: Saturday, December 18, 2004 9:32 AM To: PDML Subject: "safe" Flash Sync Voltages
All the talk about 'safe' flashes to use on the D got me a little concerned. The last thing I want to do is damage the poor thing. :-( I took some measurements from various units that I use.
Here are the sync pin voltages I measured from various flash units:
Pentax 200T 4.65 Pentax 280T 7.18 Pentax AF-360FGZ 3.01 Pentax AF-500FTZ 3.55 Vivitar 285HV 5.80 Vivitar 285 6.24 Yake M-110 Studio Flash 8.09
I no longer have an O'Scope so I can't measure any 'spike' voltages present at the sync pin when fired. These spikes are what could do real damage. In a properly designed trigger circuit there should be no spikes but I can't prove their presence or absence on these units.
As far as I can see the ist D manual only mentions these flash models:
240,330,360,400,500.
The 360 and 500 I measured are the lowest sync pin voltage of the lot. This leads me to believe that the newer Pentax's are designed to operate at lower, (sub-TTL logic) levels. I'm reasonably OK with the 200T but the Yake and the 280T really scare me.
There is such a thing as a "flash isolator" available. It fits in the hot shoe and protects the camera from overvoltage/spikes at the sync pin.
I will be buying one very soon for the 285s and Yake! I will also not be using the 280T on the D anymore.
Don
