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 :-) I'm posting without his
consent, but I don't think there is any private stuff here that would offend
Chuck.
Wayne
Wayne Culberson wrote:
> Hi Chuck,
>
> Well, I finally got the three Vivitar 550FD flashes today. The guy was
> really slow in getting them mailed out. It was a bit of a gamble, but I
> think I did alright. It turns out that his description wasn't entirely
> wrong, one of them is for Canon/Ricoh, but the other two are for M/P/O.
> So he must have been reading from one box label, and photographing
> another one. Still, guess I can't complain at $9.99 plus shipping. All
> three are NIB, and all charged right up with no problems. I did snap
> them off a few times to form the capacitor as you advised.
>
> The Canon/Ricoh one I was thinking of keeping, perhaps for a manual or
> auto flash for one of my rangefinders (Olympus RC), but when I tried it
> out, the extra pins on its shoe just barely contact the bare metal of
> the camera hotshoe. On the OM hotshoes, the non-conductive part behind
> the center pin contact is wide enough to cover the extra pins, but not
> on the rangefinders. So, I'm wondering if it is safe to turn on the
> flash when the extra pins are in contact with the metal part of the
> camera. I'm thinking the flash must put a bit of power on these extra
> pins, obviously in TTL mode, but maybe even in auto and manual mode.
> Since you mentioned using them on the optical hotshoe, I'm wondering if
> you have any problems this way.
>Wayne
---------------------------------------
(Chuck replied)
As it turns out, I had only ever used T-32's in the optical slave shoe
and the T-32's retract their TTL pins when in a non-OM/TTL shoe. The
550FD doesn't have this mechanical sophistication but I thought the TTL
pins might still be electrically protected since it's designed for use
on multiple cameras.
I had a closer look at the optical slave shoe and it definitely has a
lot of uninsulated metal surrounding the main contact but there is some
insulated area. On the 550FD the two M/P pins at the rear *definitely*
contact the metal area. The two OM pins at the front (one of which is
probably also used on the Minolta or Pentax) are *probably* touching the
metal area. I can't see them, of course but, by measurement, I think
they're about 1/2-1mm onto the metal area. Since such a small
measurement is a bit uncertain I can't be 100% sure they're touching. I
decided to be adventurous anyhow and try it.
The first thing I discovered was that the 550FD would only go into the
slave shoe in one direction (slave sensor at front). The T-32's will go
in backwards or forwards which allows positioning the slave sensor at
either front or rear. The things are so incredibly sensitive, however,
that it probably doesn't make any difference.
The slave readily fired the 550FD. Afterwards, I checked it in manual
and both auto modes and it worked fine. Then I put it away and only
later realized that I hadn't tested the TTL mode on an OM. So I did
that this morning and all is fine.
I did have a bit of a scare at first when the TTL mode on the 550FD
appeared to be operating erractically and I thought maybe I had damaged
it. The first shot worked as expected but all my follow-on shots were
reporting "over" exposure. I then substitured the T-32 and found it to
be working correctly 100 percent of the time.
To make a long story short, what I eventually discovered is that the
550FD is not as fast as the T-32 as regards quench time. It has a very
definite minumum range which is longer than the T-32's. I had been
shooting at ISO 100 and f/2 in a small room with white walls and ceiling
and light colored furniture and a large mirror. The T-32 had no problem
with this. But looking in the 550FD manual (inside back cover) I
discovered that minumum distance for ISO 100 and f/2 is 6 feet. I was
probably actually about 8 feet away getting overexposure indications but
attribute that to the overly white room. I then closed down a stop or
two and also tried just backing up a few feet and then all worked as
expected reporting proper exposure.
In the end I got a more extensive test than I planned since I hadn't
previously thought about testing the overexposure indication.
So, I'm about 90% certain that putting the Canon unit on your
rangefinder and shorting the TTL pins will not damage the flash.
However, I can't be 100% certain that the OM TTL pins were shorted.
Given your investment of maybe 5 bucks for the flash (counting shipping)
I don't think I'd be afraid to experiment. Especially since you
probably have no intention of ever using the Canon TTL mode.
Let me know what you decide and what you discover.
Chuck
--------------------------------------
Hello again Chuck,
I decided to break out a tester that I got for Christmas to see if I could
discover anything. Here is what I found, keeping in mind I am electonically
challenged. (Maybe we should take this over onto the Olympus list to see if
any of the guys over there could shed any light.)
The Vivitar 550FD triggers at 4 volts according to my measurements, whereas
the T20's and T32 I have trigger at about 1 volt. This seems to not agree
with the figures on this page http://www.botzilla.com/photo/strobeVolts.html
, so don't trust anything I say without checking it yourself :-)
It does seem to me though that since the T series and Vivitar 550FD trigger
at the same polarity, albeit slightly different voltages, and the forward
pins are of the same reverse polarity, albeit slightly different voltages,
they should be safe to use in series with connecting cords if you wanted to
use them together to make up the 9 or less flashes allowed in TTL on OM's.
Both the Olympus T series and Vivitar 550FD M/P/O model put out power onto
one (left I think if viewed from the rear) of the forward pins, the Olympus
at about 4 volts, and the Vivtar at about 2 volts. But quite interestingly,
both of them put out power onto the forward pins at reverse polarity. Now
this is where I am electonically challenged, as I have no idea if this is of
any consequence, but for safety of the flash's sake, I don't think I'd want
them mounted on any shoe that shorts the forward powered pin. Of course,
this is not an issue with the Olympus flash as the extra pins are
mechanically raised out of contact on any shoe other than and OM, but that
is not the case with the Vivitar 550FD, as you noted.
Also, the Vivitar 550FD puts power onto the extra pins regardless of whether
the flash is set in manual mode, auto mode, or TTL mode. I suppose this was
for the sake of simplicity, and perhaps for any cameras that set the shutter
speed automatically by these flashes. So none of the pins are neutralized by
setting the flash in manual mode.
Both the C/R and M/P/O versions of the Vivtar 550FD have 4 pins behind the
center trigger pin, although the C/R version's pins are a bit further back
to line up with Canon and Ricoh cameras. Some of those pins also put out
power in the range of about 2 to 4 volts. On the M/P/O version, one of the
rearward pins puts out what seems to be a pulsating power, from 2 to 4
volts. I'm not sure what pins accomplish what of course on Pentax, Minolta,
Canon or Ricoh cameras. All of the powered pins behind the center pin put
out in normal polarity.
We discussed earlier the possibility of using the Vivitar 550FD on the
C5050. As to trigger voltage, it seems within a safe range, but on both the
C/R and M/P/O versions, some of the 4 pins in the rear position would almost
certainly be in contact with the 3 rear pin positions on the C5050 camera
hot shoe. So obviously I wouldn't feel safe using them.
There seems to be no easy way of keeping the extra pins on the 550FD
mechanically raised, as each one is on its own individaul spring. So, what
I'm thinking of trying, is taking the shoe off the Vivitar 550FD C/R
version, clipping all the wires that lead to the rear four contacts
(assuming there are wires :-), and capping them with a bit of epoxy or
something. That should leave me with a flash that only powers onto the
center trigger pin, so a flash that can then be used safely with the C5050
or with any hotshoe. It should work in both auto modes and in manual mode,
and if put accidentally in the TTL mode it would perhaps/probably just
continue to work in full manual.
As you have said, the Vivitar 550FD doesn't have the cut off range of the
T32. Olympus always seems to be a step or 3 ahead in some ways. But the
Vivitar does have a more easily used bounce flash head, and I also like the
way it is a bit higher than the T series to get it a bit further away for
reduced chance of redeye. The Vivitar GN of 24/80 is measured at 50mm
according to the way I read the manual, so is quite different that way than
the T32 which is measured for 28mm angle, and the T20 which is for 35mm
angle. So the Vivitar might not quite match the widest settings on the C5050
(35mm equivalent), or the 42mm of the Olympus 35RC, but I doubt it would be
too noticeable. I'll have to experiment.
Wayne
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