Chuck,
it is quite possible they put the scr trigger isolator on the external
flash sync socket to
isolate it, from the camera *and* from the system flash (hot shoe flash) at
same time. This
protects the system flash from hi voltage as well as the camera. (In fact they
could add an
isolating diode to the system flash to protect it internally and still allow hv
trigger
simultaneously. ) But it would make more sense to isolate both to a hi
voltage.
So it is possible, though not very likely the hotshoe would be isolated to only
a low volage and
the sync socket to a hi-voltage.
In general it actually does make a lot of sense to isolate them seperately, so
as not to have
weird trigger interactions and the possibility of damaging a $500 system flash.
With a multimeter/ohmeter you could actually check if the hotshoe is wired
directly to the ext
sync socket. (with Camera switched off)
Tim Hughes
--- Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx> wrote:
> The problem is not so much determining what the trigger voltage is on
> the flash unit but rather determining how much the camera is designed to
> withstand. If you have the flash unit in hand you can easily measure it
> yourself with a volt meter. But there's no way you can tell what the
> camera can take unless the manufacturer tells you.
>
> On Sep.7, 2006 Nils Frohberg sent a note to the list advising us all
> that Olympus Europe tech support had sent him email advising that his
> E-500 and all E-system cameras were protected to 200 volts on the hot
> shoe. Then I think John Hermanson got some conflicting information from
> Olympus America but it was vague enough that I didn't bother recording
> it. Both the E-1 and E-3 manuals note that the PC connection is good to
> 250 volts. The manuals for the other cameras which do not have a PC
> connector don't make any mention of flash voltage but do give
> instructions on using non-E-system flash units. The only caution is
> that TTL connections for other than E-system flashes may be trouble.
> Given that the E-1 and E-3 PC connections are good to 250 volts I think
> the info Nils was given is at least suspect... probably drawn from a
> tech's faulty memory rather than from a written technical spec. I don't
> see why a hot shoe would be good only to 200 volts if the camera's PC
> connector is good to 250.
>
> On the link below you will see a note implying Canyon is only good to 6
> volts. Such was true for the early EOS digital cameras D30 and 10D. As
> stated in the user manuals, the later cameras (from 20D on) are good to
> 250 volts on the PC connection. I think the same holds for the hot shoe
> but the wording in the user manuals is a bit vague on that.
>
> An then we have the wonderful Mynolta A1 which claims the PC connector
> is good to 400 volts. But once again the status of the hot shoe is left
> unmentioned. I don't think there's any reason to believe the hot shoe
> and the PC connector are on different circuits and therefore have
> different maximum voltage levels but I suppose they could be.
>
> Dr. Flash
>
>
> Jim Couch wrote:
> > I got this link from one of the Nikon lists I lurk about on. A great
> > resource that gives trigger voltages for a ton of flashes. I thought it
> > might be helpful for those trying to see if that old Sunpack or Vivitar
> > flash sitting in the closet will work with your beloved Olympus digital.
> > (Just to keep it on topic!)
> >
> > http://www.botzilla.com/photo/strobeVolts.html
> >
> > Jim Couch
> >
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> >
> >
> >
>
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