I've been trying to find info on just what the sync contact is actually rated for amp/volt wise. When I contacted Olympus about my C5050 digital I was told 'absolutely not to use' the Vivitar 285 without a flash isolator. It wasn't due to the voltage in that case but the surge current when fired. Since I never use the 285s on the hot shoe anyway it's no trouble to use the Wein device. For $50.00 it will give me a lot of peace of mind. Especially when 100+ miles from home shooting something for money rather than fun. Losing flash ability wou really 'hoover'! (My new favorite word) ;-)
Don > -----Original Message----- > From: Mat Maessen [mailto:[EMAIL PROTECTED] > Sent: Saturday, December 18, 2004 11:05 AM > To: [EMAIL PROTECTED] > Subject: Re: Isolators_Was- "safe" Flash Sync Voltages > > > I wouldn't worry about 7-8 volts on the flash terminal. Now 70-80 > volts, I'd worry about. :-) > > -Mat > > > On Sat, 18 Dec 2004 09:49:11 -0600, Don Sanderson > <[EMAIL PROTECTED]> 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 > > > > > > > >
