At 10:10 PM -0400 5/30/06, Joe Gwinn wrote:
>Date: Tue, 30 May 2006 21:03:08 -0400
>From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxx>
>Subject: [OM] Re: T32 on an E1 - d'oh!
>
>Ah, more fear, uncertainty and doubt (FUD) peddled by the vendors of
>"safe sync" hot shoe adapters. A quick $50 for the seller peddling a
>mostly unnecessary part.
Hmm. I didn't know of their FUD. What would be useful is something
to convert between the hotshoe contact patterns. Do any do that too?
Given names, I'll do some digging.
>The Metz flash will almost certainly provide a male PC connector to plug
>into the E-1's female PC connection. Oly doesn't spec the hot shoe for
>us but the E-1's PC connection is rated at up to 250 volts. See page
>106 of the E-1 Reference Manual.
The e-500 "Advanced Manual" has no such information, although I bet
that the e-500 and E-1 use the same circuit. Nor does the e-500 have
a PC connector that I've found. (I've been using the pipsqueak
built-in flash to optically trigger my studio flash units; this works
well, but the camera must be used in manual mode with ISO set to 100.)
That covers one contact out of five. The OM-4 five contacts as well,
one large, four small, but in a different physical pattern. There is
a good chance that the E-series cameras use much the same hotshoe
circuits as the OM-4, at least functionally, but with a different
arrangement of contacts. One possible arrangement:
1. The big contact shorts to ground to trigger the flash.
2. One small contact shorts to ground when the camera has seen
enough light. This is the flash TTL exposure control function.
3. One small contact tells the camera when the flash is ready to
fire by illuminating a light in the viewfinder. This light was
powered by the camera in the old days, which ran the camera battery
down, and may now be powered by the flash.
4. One small contact tells the camera that the flash was terminated
before the full flash was emitted, implying that the commanded TTL
exposure was achieved.
5. One small contact (and the shoe rails) is ground. In the
e-series cameras, this small contact has a hole into which a pin from
the flash goes, apparently to prevent the flash from drifting out of
the hot shoe. On the OM-4, no little hole, and this contact may do
something different than on the e-series.
>Next you need the specific voltage of the specific Metz flash. If you
>have the flash in hand just measure it. Or, if you only know the model
>number you can look it up here:
><http://www.botzilla.com/photo/strobeVolts.html>
>Some very old flashes might have high trigger voltages but any
>reasonably modern Metz unit will likely fall about in the 6V range.
I think all current flashes use something like 6 volts. I do have
the equipment to measure trigger voltages directly. A typical value
for older flash units is one half the flash voltage, or 160 Vdc.
Joe Gwinn
>
>Chuck Norcutt
>
>Joe Gwinn wrote:
>
>> At 3:29 AM +0200 5/29/06, Listar wrote:
>>
>>>Date: Sun, 28 May 2006 10:57:00 -0300
>>>From: John Hudson <OM4T@xxxxxxxxxxx>
>>>Subject: [OM] Re: T32 on an E1 - d'oh!
> >>
>>>
>[snip]
> >
>> There is a more general question to be answered: What do the various
> > E1/eVolt hot-shoe contacts do, and what are their voltage/current
>> expectations and tolerances? I have not seen anything from Olympus
>> on this, but the information must be somewhere. The physical
>> arrangement of contacts is different from that of the OM-series
>> cameras, but what is communicated between flash and camera must be
>> mostly the same.
>>
> > Joe Gwinn
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