I have a brand new VIVITAR 550FD (never used still in box). What is the
thought of using this with OM bodies?
I never tried mine...since I have a T32. I also bought the PROMASTER Oly
module in hopes of buying a 5000 series flash someday.
Last time I saw one on Eb*y...they were going for $ 5.00 - $ 15.00. I
paid $ 30.00 at a local camera shop.
- Ali
Joe Gwinn wrote:
>At 3:52 AM +0100 1/2/05, Listar wrote:
>
>
>>From: "Wayne Culberson" <waynecul@xxxxxxxxxxxxxxx>
>>Subject: [OM] Vivitar 550FD M/P/O discussion
>>Date: Sat, 1 Jan 2005 16:42:37 -0400
>>
>>The following is part of a discussion Chuck Norcutt and I've been having off
>>list about some uses and safety issues with Vivitar 550FD
>>Minolta/Pentax/Olympus dedicated flashes. I think our discussion started on
>>the Vivitar or Kiron lens list. (Chuck had recommended these flashes some
>>time ago, so I've been watching for one on the auction site.) I thought
>>maybe someone here might be able to offer some insight, providing of course
>>anyone has the patience to read all this below....
>>
>>
>
>A few things occur to me.
>
>1. Voltage measurements at
>http://www.botzilla.com/photo/strobeVolts.html seem to vary all over
>the place, which I suspect is due to the various kinds of voltmeters
>people have. Many synch circuits consist of a capacitor charged
>through a large resistor, with 1 megohm being common, so the
>voltmeter impedance must exceed 10 megohms for reasonably accurate
>measurements. Many cheap voltmeters have far lower impedances, and
>will load the synch circuit down, causing false readings. And, one
>must wait for the voltage to stabilize.
>
>2. ISO standards (ISO 10330 "Photography -- Synchronizers, ignition
>circuits and connectors for cameras and photoflash units --
>Electrical characteristics and test methods," 1992; this may be in
>the process of revision) do carry considerable weight in the photo
>world, but are not retroactive. This means that the next generation
>will meet the 24-volt standard, but current production is what it is.
>I hope and assume that this ISO standard also makes the manufacturers
>all use the same polarity.
>
>3. I doubt that shorting the TTL pins on Olympus (or anyone else's)
>flashes will cause any damage, as a flash that wouldn't work (let
>alone would be damaged) in a plain old one-contact metal hotshoe
>would be laughed out of the market. That said, if Olympus went to
>the trouble of mechanically retracting the extra pins, it may be that
>shorting those pins will interfere with flash operation.
>
>4. It's probably OK to parallel flashes that have the same
>low-voltage polarity (plus or minus) on their synch terminals, even
>if the voltages are not exactly the same, so long as the voltages are
>all no more than 10 or 15 volts. If the polarities are opposite, the
>units will likely keep each other from working, but probably won't
>hurt each other. But, no manufacturer will guarantee this, because
>they cannot test all combinations, and are responsible only for their
>own products.
>
>Joe
>
>
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