safe synch for studio strobes? please help

[nucki]

Hi!

in a few days I have the chance to shoot a professional model. I get a 3000 WS studio strobe and was wondering if I need a safe sync for that. But the strobe will be connected to the PC socket of my 10D. Do I need anything to avoid high voltage spikes? or is that save synch just for the normal hot shoe?

pleas help! thanks!

best regards
Peter

[kiwikeith]

I have used my 10d with studio lights (Bowens Esprit 11 500ws + smaller,older bowens monolight) for the past 12 months with sync cord and no problems (touch wood) so far..
that said, the trigger voltage for this camera even with the sync cord attached to the pc connector is 6 volts..if you are really worried about or dont know what the trigger voltage is on your light then by all means use the safe sync or better yet the radio triggers that are available....
I have yet to hear of any anecdotal info/evidence regarding electronic problems with the camera directly related to the use of unsafe trigger voltage...
KK

[chris.bailey]

Better to be safe than sorry. Most studio strobes sync at voltages much higher than 6v. My Bowens units are 24v and some others are even higher. The contacts on the 10D are pretty small so would easily arc over resulting in a high repair bill.

I ALWAYS put a Wein Safe Sync between my studio flashes and my camera.

[scottbergerphoto]

A Safe Sync or even a set of Pocket Wizards is much cheaper then a new shutter. Better safe then sorry.
Scott

[nucki]

thanks!

now I got the info, that the flash is connected to the x-sync. and that the power comes from the camera and not from the flash. I'm not sure. I hope my camera will survive :)

best regards
Peter

[flyfishnj]

More info on Strobe voltages

http://www.botzilla.com/photo/strobeVolts.html

[nat869]

I would definitely use a Wein Safe Sync. They are a lot less expensive than getting any repairs done to your camera. Evidentally any voltage over 6V will damage the camera. Electricity definitely flows from the light to the camera, do not be fooled, it is not a one way street. If you doubt it, just use a multi-meter and check. Have fun with the photo shoot, post some results for us.

[scottbergerphoto]

I would definitely use a Wein Safe Sync. They are a lot less expensive than getting any repairs done to your camera. Evidentally any voltage over 6V will damage the camera. Electricity definitely flows from the light to the camera, do not be fooled, it is not a one way street. If you doubt it, just use a multi-meter and check. Have fun with the photo shoot, post some results for us.
That is correct. The flash trigger voltage is measured on the flash and not the camera.
Scott

[WestFalcon]

I have used White Lightning 1200 Ultras with no problems..They have a sync voltage of 9 or so. Canon says 6v on the 10D so I guess I must be lucky. The new 20D(if you get one to replace your 10D) can take 250v so that should not be a problem with any modern flash. I have just purchased some pocket wizards and absolutely love them. PC cords are a pain in the butt.

[robertwgross]

To phrase it differently, the high or low voltage is inside the flash unit. Some "DC trigger voltage", whether that is high or low, will appear on the cord connector where it plugs into the camera. When the camera's shutter is released, a momentary short circuit is placed across that electrical plug, through the cord, to the flash unit.

If you have a multimeter, you can directly measure that trigger voltage on the connector.

The flash power is inside the flash unit, stays inside the flash unit, and is only triggered at the camera body. However, depending on how you do it, you may or may not fry part of the camera's shutter circuit.

---Bob Gross---

[nucki]

To phrase it differently, the high or low voltage is inside the flash unit. Some "DC trigger voltage", whether that is high or low, will appear on the cord connector where it plugs into the camera. When the camera's shutter is released, a momentary short circuit is placed across that electrical plug, through the cord, to the flash unit.

If you have a multimeter, you can directly measure that trigger voltage on the connector.

The flash power is inside the flash unit, stays inside the flash unit, and is only triggered at the camera body. However, depending on how you do it, you may or may not fry part of the camera's shutter circuit.

---Bob Gross---

Thanks to all again! Bob, can you tell me how to measure the trigger voltage? if I understand you right, I measure at the pins from the flash? right? between wich pins? if so, it should be possible to measure this also at the studio flash?

thanks
best regards Peter

[robertwgross]

can you tell me how to measure the trigger voltage? if I understand you right, I measure at the pins from the flash? right? between wich pins? if so, it should be possible to measure this also at the studio flash?


OK, you have a short cable that comes from the flash unit (or studio flash) and connects to the camera. In that cable, there is a center pin and then there is an outer round piece. Those are the two electrical conductors.

If you want to blind yourself, then turn on the flash, let it wind up, and then stick a screwdriver or paper clip across the two conductors. It will flash.

Let it wind up again, and this time use a multimeter set to a scale for DC volts. Some flash units use 200 volts or more, and some use only 5 volts. Anyway, if you put the meter probes across the two conductors, you should be able to read the trigger voltage without firing anything. If you slip and let one probe touch both conductors, then it fires the flash and you get blinded again.

The current family of modern Canon Speedlites (xxx-EX) will show about 5 volts.

---Bob Gross---

[nucki]

OK, you have a short cable that comes from the flash unit (or studio flash) and connects to the camera. In that cable, there is a center pin and then there is an outer round piece. Those are the two electrical conductors.

If you want to blind yourself, then turn on the flash, let it wind up, and then stick a screwdriver or paper clip across the two conductors. It will flash.

Let it wind up again, and this time use a multimeter set to a scale for DC volts. Some flash units use 200 volts or more, and some use only 5 volts. Anyway, if you put the meter probes across the two conductors, you should be able to read the trigger voltage without firing anything. If you slip and let one probe touch both conductors, then it fires the flash and you get blinded again.

The current family of modern Canon Speedlites (xxx-EX) will show about 5 volts.

---Bob Gross---

Thanks Bob, I will try this!

[robertwgross]

For those who do not own a multimeter and are considering to purchase one:

These days they don't sell very many analog meters, and most are digital. If you fool with electronics a lot, then you may get a really good multimeter that costs $100 or more. However, for a typical photographer, all you need to measure is a flash trigger voltage, or maybe the voltage on some batteries, something on the car, or maybe something else simple like that. A simple digital multimeter should be sufficient.

My local electronics store had some excellent (cheap) multimeters for $20. I generally keep one in my electrical fix-it bag in the trunk of my car.

---Bob Gross---

[evilenglishman]

Could someone point me to info where Canon has SPECIFICALLY said that the voltage can be no higher than 6v ??

[scottbergerphoto]

Could someone point me to info where Canon has SPECIFICALLY said that the voltage can be no higher than 6v ??
"Trigger circuit voltage.

Old flash units - both studio and hotshoe-mount - used pretty high voltages between the camera and the flash - often from 25 to 250 volts. This is because the flash units were fired by simple switches - electrical contacts.

Modern cameras, however, rely on electronic circuitry rather than electric switches. This allows for more flexibility and the possibility for computerization, but the circuits can’t withstand high trigger circuit voltages (anything above 6 volts, in the case of EOS cameras, according to Canon) and can be damaged by units with high trigger voltages.

Note that this 6 volt limit does not necessarily apply to PC sockets. Canon states that its 1D digital camera, for example, is capable of withstanding trigger voltages of up to 250 volts when firing flash units with its PC socket. The 6 volt limit applies to the camera hotshoe only. Unfortunately Canon doesn’t always state what trigger voltage the PC sockets on all of its PC-socket-equipped cameras can withstand, so if this information is not supplied in the manual you should probably contact Canon.

Anyway. If you intend to connect an old flash to your EOS camera’s hotshoe be absolutely sure that its trigger voltage does not exceed 6 volts. You can measure this with a voltmeter. Various accessories, such as the Wein Safe-Sync HS hotshoe unit, can be used to protect the camera from these high voltages if you want to use such a flash. Even safer are optical triggers, since there are no physical connections between the camera and flash unit at all.

Note that the damage to the camera can be subtle and cumulative - simply hooking up the flash and seeing if it works is no guarantee that the high voltage isn’t slowly damaging your camera’s flash circuit - arcing and pitting connectors and breaking down internal components. (of course, Canon is probably being a bit conservative with its 6 volt limit, so you might not be taking a huge risk if the voltage of your flash unit is a tiny bit over) Note also that the power supply used by the flash is irrelevant - it has no bearing on the trigger voltage. Many Canon Speedlite flash units, for example, can use high voltage battery packs but they still have low trigger voltages. And portable battery-powered flash units may require 6 volts in battery power but nonetheless may step up the trigger voltage considerably.

An additional problem is that some older flash units have reversed polarity. EOS cameras all have a negative ground and a positive centre pin on the hotshoe itself, though some pro models have polarity-detecting PC connectors that can work with either type of flash unit.

Finally, some flash units have all-metal hotshoes. This can be a problem if they inadvertently short out any of the four small data contacts on EOS cameras. If you have such a camera you could cover up the contacts with electrical tape or use a PC cord adapter so the flash unit doesn’t plug directly into the camera’s hotshoe mount at all. The same applies if your flash unit has a really large central contact. EOS cameras have fairly small hotshoe central contacts with four tiny data contacts below it. If your flash unit’s hotshoe contact is so large that it shorts out any of the data contacts you may damage your camera.

The old Canon EOS FAQ also has a great deal of information on the subject of trigger voltages, and Kevin Bjorke maintains a comprehensive table of trigger voltages for various flash units. "

From: http://photonotes.org/articles/eos-flash/index2.html#trigger

I've read that the 20D can handle 250volts : http://www.photoworkshop.com/double_exposure/publish/article_936.shtml
Regards,
Scott

[DAMphyne]

I burned-out the flash trigger on my D30 with my Novotrons.
Cost 400 bucks to repair.
Just thought I'd let you know. I used it for months with no problem, then one day, crash.
Buy the safe Sync, it's cheap.

[Mark_Cohran]

A cheap and easy way to trigger your flashes (if you have an external flash like the 550EX) is to place the flash in manual mode and set it to 1/128th power and use that to trigger the optical slaves on your studio strobes. It's safe, wireless, and works like a champ for me.

Mark

[RDKirk]

I burned-out the flash trigger on my D30 with my Novotrons.
Cost 400 bucks to repair.
Just thought I'd let you know. I used it for months with no problem, then one day, crash.
Buy the safe Sync, it's cheap.

According to the way Chuck Westfall described it, it's better described statistically: Nearly 100 percent of the shutters will never fail if the voltage is less than 6 volts; nearly 100 percent of the shutters will fail immediately if the voltage is over 12 volts. Between that range, some shutters may last quite a while, others may fail immediately.

According to the manual, the 20D does have a 250v PC terminal, but the manual reads as though the hotshoe is different. But it says a higher voltage flash won't work--not that it would damage the camera. I'm not sure what that means.

[RDKirk]

I burned-out the flash trigger on my D30 with my Novotrons.
Cost 400 bucks to repair.
Just thought I'd let you know. I used it for months with no problem, then one day, crash.
Buy the safe Sync, it's cheap.

According to the way Chuck Westfall described it, it's better described statistically: Nearly 100 percent of the shutters will never fail if the voltage is less than 6 volts; nearly 100 percent of the shutters will fail immediately if the voltage is over 12 volts. Between that range, some shutters may last quite a while, others may fail immediately.

According to the manual, the 20D does have a 250v PC terminal, but the manual reads as though the hotshoe is different. But it says a higher voltage flash won't work--not that it would damage the camera. I'm not sure what that means.