canon and studio lights

zephyrphoto · March 14, 2006

There are stories about canon's being damaged by high trigger

voltage on flash lights.

I called canon and they say this is not the case, and the only

damage that can be done is if the polarity on the PC cable is the

wrong way round.

Does any body actualy know anyone who has damaged a camera? or is

the trigger voltage thing an urban myth.

andrew_carlson · March 14, 2006

The theory is that older studio lights carried high voltage, like 250-400v. Most analog camera's could handle this and again, theory is that some required it. Digital cameras use about 6v on the PC sync. Well the difference between 6v and 400v is quite amazing. Even Novatron's website discusses this and claims any units made after something like 2000 are safe.

For concerned users there is the Wein safe sync and other remotes to control the studio strobes. The idea is to put an inexpensive filter or regulator in place, or use a remote. I chose to do it when I bought an older novatron kit off Ebay. The price was right, but the manufacture date was early '90s.

To me, a $20 or $30 piece that might save me from extensive repairs is worth it. On the one hand, if the possibility exists that my body could be damaged, wein has a guarantee. On the other hand, if its not possible, $20 or even $40 for a little piece of mind isn't really hurting me. If it were $200 I'd reconsider it.

What I found out bouncing from camera store to camera store in in Colorado was that many store clerks didn't have a clue as to what a wein safe sync was. I could have been talking greek to them.

rdkirk · March 14, 2006

How can this be an "urban myth" when the instruction manuals for the 10D and the original DRebel warn against it?

However, it's true that the CURRENT lineup of Canon DSLRs are resistant to sync trigger voltages up to 250 volts...but there are still some older flash units around that are yet above even that.

This is what Canon's US director of technical information, Chuck Westfall, has said about the issue:

From a search of the Rob Galbraith forums (www.robgalbraith.com).

Re: For Chuck Westfall/trigger voltage on 1D mkII [Re: JuliValley]

#248688 - Thu Jun 24 2004 02:23 PM Edit Reply Quote Quick Reply

"The trigger circuit voltage (TCV) rating for any EOS digital SLR is the same on the

hotshoe as it is on the PC terminal (if the camera has one), but the acceptable TCV level

varies according to the camera model. For EOS-1D, EOS-1Ds, and EOS-1D Mark II, acceptable

TCV is 250V. For EOS D30, D60, 10D and Digital Rebel, acceptable TCV is 6V.

Incidentally, the main reason for the difference is the way the X-sync signal is

generated. With the 250V cameras, the X-sync signal is generated electronically. With the

6V cameras, the X-sync signal is generated mechanically. It would be great to have

electronic X-sync in all EOS digital SLRs, but electronic X-sync costs more. I have no

idea how much more, because Canon Inc. isn't talking about it.

Regardless of the explanation, sync filters like the Wein safe-sync are a good idea when

using non-dedicated flashes with a 6V camera.

--------------------

Chuck Westfall

Director/Media & Customer Relationship

Camera Division/Canon U.S.A., Inc. "

Re: Terminal Voltage Dangers [Re: Michael_Fontana]

#171648 - Mon Sep 29 2003 08:00 AM

I've answered questions on this topic several times this year. Here is a compilation of

the important material:

1. We recommend that you check the voltage coming out of your sync cable before you plug

it into your EOS 10D. If it is significantly higher than 6 volts, then we suggest that you

obtain and use a sync filter that fits between your power pack and your sync cable to cut

the voltage level down. If this is not an option for you, consider the use of a radio

slave.

2. If the 10D doesn't fire your studio strobes, check the polarity of the sync cable as

well as the voltage. You should have plus (+) polarity on the cable's pin. The shield

surrounding the pin should be ground, or minus (-). If this is not the case, reverse the

polarity of the cable.

>>When you say "significantly higher than 6v" do you have any guidelines as to what is

"significant?"<<

My recommendation would be to keep the sync voltage as low as possible when using the 10D,

D60 or D30. 6 volts is a safe figure for these models. Generally speaking, sync voltages

up to 19 or 20 volts won't cause any immediate problems, but they may shorten the life of

the shutter. We always recommend a sync filter whenever sync voltage exceeds 6V with the

10D, D60 or D30. (The corresponding figure for 1D and 1Ds is 250 volts.)

>>And does the limit apply to the PC outlet as well as to the hot shoe?<<

Yes, because the sync signal with these cameras (10D, D60, D30) is generated mechanically

at the shutter. The sync terminals, whether hot shoe or PC socket, are both connected to

the shutter.

>>Is there any sign of damage being done? Or is it a gradual buildup of damaging arcs on a

circuit board that will hold up for a while and then all of a sudden fail at some point?<

There's no externally visible sign of damage. However, excessive sync voltage can shorten

the life of a 10D, D60 or D30 shutter. You'll know you've got a problem when the camera

can no longer fire an external flash unit. When that happens, the shutter unit must be

replaced. This is not a difficult thing for an authorized service technician to do, but

it's relatively expensive. I won't quote an exact price, but you're looking at several

hundred dollars for parts, labor and a 6-month warranty. Keep in mind that shutter damage

caused by excessive sync voltage is not covered by the warranty.

Let me know if this answers your questions!

--------------------

Chuck Westfall

Director/Media & Customer Relationship

Camera Division/Canon U.S.A., Inc.

Re: 10D PC Socket trigger voltage (for Chuck?) [Re: Keith_Strickland]

#150942 - Tue Jul 15 2003 03:48 PM Edit Reply Quote Quick Reply

Hi, Keith:

Thanks for clarifying your question. I've already addressed this issue here about 6 weeks

ago in message #136880. Here's a relevant excerpt: