I think you're probably right and it would be fine on all the flashes I listed and the 400T. For $50.00 however I'll get a lot of peace of mind. I don't use the 285s on the shoe anyway so it's no hassle to use the isolator.
Don > -----Original Message----- > From: Paul Stenquist [mailto:[EMAIL PROTECTED] > Sent: Saturday, December 18, 2004 10:08 AM > To: [EMAIL PROTECTED] > Subject: Re: Isolators_Was- "safe" Flash Sync Voltages > > > I use my Pentax AF 400T and my Studio Pro mono lights on the *ist D > constantly. I must have more than 1000 firings without incident. > 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 > >> > > >
