Not to Raise/Beat a Dead Horse, but....Trigger Voltage

[flint350]

I, sadly, had the occasion yesterday to send in my 10D for shutter lock repair. It wasn't caused by overvoltage equip. bcz I don't exceed the 6V Canon limit. However, in talking with Canon and further research, I found this from Chuck Westphal on another forum:

...as Chuck Westfall (USA Canon technical information director) puts it, the damage pattern is described more statistically: (speaking of the 10D at the time) nearly 100 percent of samples will be perfectly safe at 6 volts or below; Nearly 100 percent of samples will be damaged at 12 volts or above; between 6 volts and 12 volts, the percentage will vary, with failures increasing as the voltage increases. So just because John Doe's 300D works perfectly well with a 12 volt flash unit, it doesn't mean yours will--the odds are still against you.

This clearly indicates (to me anyway), further proof that Canon was not bound by, or at least didn't adhere to any ISO standard of 24V trigger voltage as someone else insisted. The statement that "nearly 100% will be damaged at 12V" says it all.

I'm not trying to re-open any sore topics, just bringing info from Canon's own USA Tech Rep about the 10D - simply for informational use of those who use a 10D and have any concerns about trigger voltage. I'm glad I didn't void my warranty. Others are certainly free to do as they wish and heed/ignore this statistical information.

[Mikefellh]

It's amazing how cheap camera manufacturers are...there are external devices (like the Wein Safesync) that are able to clamp down the voltage to a safe level for these cameras, why can't they put that technology IN TO THE CAMERA? Why don't the camera manufacturers put warning labels on the camera to let you know of this issue?

If these cameras (like the 10-D) are aimed at pros, then the manufacturer should realize this issue.

I just bought a dock for my father's inexpensive camera the other day, and right on the dock there's a warning label to take out the alkaline batteries and replace them with NiMHs, otherwise you would damage the camera when the dock tries to recharge the alkalines!

[KCan]

Mikefellh wrote:

It's amazing how cheap camera manufacturers are...

Indeed :flame:

Mikefellh wrote:

why can't they put that technology IN TO THE CAMERA?

IMO, cameras do not need any of those extra "technologies", it`s just the final output devive that have to be more robust (and $$$) ... may be 10 cents and an extra 2 or 3 cubic mm more per camera :?

Mikefellh wrote:

Why don't the camera manufacturers put warning labels on the camera to let you know of this issue?

IMO, they don't want anyone to identify any of their camera's "issue" :G

[NHL]

Well I have a miracle to report because according to the statistics my 10D should be 100% dead by now!: My old Metz 45CT-5 put out 24V (actually just measured it again 24.6V with freshly charged NiMh) and I have used this flash on the 10D for over a year. It also looks like my 4 other Canon bodies that I have used and collected with this flash are still alive and kicking as well. So much for statistics hey... Here's what other Canon's users (beside me) have to say about this wedding workhorse: http://reviews.iwon.com/pscPhotograp...2_3121crx.aspx
"I have owned the 45CT-5 and the actual 45CL-4. Both are perfect machines in terma of power, versatility and rugged design. The SCA-connectors link both flashes to my old Canon A1 or (CL-4 version only) to my EOS 3. I prefer using the A-TTL-mode of this flash over the e-TTL mode of the dedicated systems (my Canon 420EX flash) since the latter tends to unexpected under- and overexposures. Read the comments of some professionals on the 550EX systems VERY carefully!"



Mikefellh wrote:

It's amazing how cheap camera manufacturers are...there are external devices (like the Wein Safesync) that are able to clamp down the voltage to a safe level for these cameras, why can't they put that technology IN TO
THE CAMERA? Why don't the camera manufacturers put warning labels on the camera to let you know of this issue?

Voltage alone is meaningless, but it's also the current flowing through the electronic switch to complete the circuit. An open voltage alone is harmless (or if its current is low enough). The Wein Safesync is not designed to limit the voltage alone: According to the ISO, this device is also intended to sink more current than a camera can withstand: for example let's take a hypothetical 6V strobe which can source 100mA and you are synchronizing 3 of theses heads to the camera (ie 3x100 = 300mA) -> you're now also exceeding the 100mA ISO limit! Which is worst? Three 6V heads @ 300mA or one 24V strobe with only 10mA sourcing capability.
Does the concept of power means anything to you guys? :idea:



KCan wrote:

IMO, cameras do not need any of those extra "technologies", it`s just the final output devive that have to be more robust (and $$$) ... may be 10 cents and an extra 2 or 3 cubic mm more per camera :?

They do. According to the ISO standard these cameras have a Zener (costing only pennies) and why the Canon manual (page 106) says that it might not fire with a higher voltage because it is clamped down by the 24V diode. Nowhere does the manual says that a higher voltage will damage the camera.


The ISO 10330 is a test method which a manufacturer uses to pass its characteristics so their equipments can be compliant for sale in the EU. This directive is NOT OPTIONAL and defininetly not for Canon which is an ISO 9000 certified company! See page 5 listing below and the other photographic Work Items (WI) that they adhere to: http://isotc.iso.ch/livelink/livelin...28026&vernum=0


The studio strobes designers did not dream up the higher sync voltage in the vacuum. Most well known professional studio strobes need the higher voltage because prior to the advent of wireless trigger, photographers required to run long lines back to their cameras. The low-voltage signaling tend to be unreliable and also triggered falsely with noise coupling through the cables. The higher voltage provides this kind of noise immunity by giving the signal a higher rejection ratio in raising the threshold...

[eric s]

While I have nothing to add, this is an interesting thread.

The things you can learn from the knowledgeable people here is great.

Eric

[flint350]

There are many sources that 'quote' Canon as saying the Hot Shoe (10D) is limited to 6V. Westfall is their USA Tech Rep and states it directly. Paramount cords (admittedly, it's in their marketing interest) also references it fully and shows photos of the CUMULATIVE damage from exceeding it - damage is not always immediate or short term. Various sites on Trigger/Sync Voltage repeat it. As an example, on Photonotes.org, they say, in part,

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.

.

They go on further to explain more, but you get the drift. There are obviously two camps out there on this issue. My question is why Canon doesn't flatly state the limit in their 10D manual (at least I never found it), but seems quick to state it thru Tech Support and all over the web. As I said, 'dead horse' issue by now, but I keep finding references to it in lots of places and now my shutter issue surfaced. So, it just made me think about it some more.

[Mikefellh]

NHL wrote:

Voltage alone is meaningless, but it's also the current flowing through the electronic switch to complete the circuit. An open voltage alone is harmless (or if its current is low enough).

Does the concept of power means anything to you guys?

Depends on the electronic switch...many IC logic circuits for instance operate only at a max of 5 volts. Too much voltage on an input and you'll damage the circuit. If the manufacturer used one of these with a 20% tolerance, of course anything higher than 6 volts can do damage.

The point that's being made here is manufacturers are skimping on parts to save money (and get more money in repairs later). All the Nikons and Canons on the shelves that have been used with higher voltage strobes are the evidence.

Some camera manufacturers are getting smarter, for instance Olympus (on their website) lists the Wein Safesync as one of the items available for their cameras.

[NHL]

Mikefellh wrote:

Depends on the electronic switch...many IC logic circuits for instance operate only at a max of 5 volts. Too much voltage on an input and you'll damage the circuit. If the manufacturer used one of these with a 20% tolerance, of course anything higher than 6 volts can do damage.

Please review your EE-101, no engineer in their right mind would use 5V IC signal to control a sync output directly... regardless of 6V (or not)!
http://www.twysted-pair.com/74lsxx.htm

May be our resident EE expert KCan can help you here... :G :G :G
http://www.pbase.com/kcan/image/1964148/original

[flint350]

Well, I don't have a degree in E.E., etc, but do take the words of the manufacturers' of their own equipment and its limits into account - and here is an official response to my e-mail question from Canon USA on this issue:

Thank you for your inquiry on the flash trigger voltage for the EOS 10D.

Please note, Canon does not supply specifications to or test with other manufacturers products. Therefore, there is always the possibility that they will not interact properly with our cameras.

If you choose to use the EOS 10D with studio lighting equipment, we suggest using a Safety Sync device to protect the camera from the voltage of the lighting system. The 10D has a maximum trigger voltage of 6 volts. Studio flash units may well exceed this voltage. High voltage flashes should not be attached to the camera.
Please feel free to contact us if you have any further questions or concerns.

Thank you for choosing Canon.

I hope this finally clears up Canon's position on this. It does for me - crystal clear. Maybe they took E.E.102
:lol:

[NHL]

flint350 wrote:

I hope this finally clears up Canon's position on this. It does for me - crystal clear. Maybe they took E.E.102
:lol:

You just managed to make a full circle! :-) :-) :-)
This is how this "Beat a Dead Horse" get started; Actually the whole web is link to this site: http://www.botzilla.com/photo/G1strobe.html

"Still, more phone calls to Canon USA reiterate their insistence that 6V is the limit for the G1 and EOS cameras.- kb 20 Feb 2001"
-> Canon USA has always insisted that their camera max limit is 6V. We all knew their position already 3 years ago... You should be all set then, nothing further should be of interest to you




"Meanwhile, in Sept 2001:
"There is not a maximum voltage requirement for the hot shoe terminal on the PowerShot G1." - Canon Canada Tech Support EMail"

For others folks like me who happened to own Metz flashes, we can at least approach this issue more intelligently:
"Recently, Rupert Vogl gave a ring to Metz and asked about strobe voltages. He was directed by them to the DIN/ISO Standards Doc #10330, which you can get as a .pdf from the ISO or the American Standards Institute for a paltry $46.

According to ISO 10330 (1992), "Photography — Synchronizers, ignition circuits and connectors for cameras and photoflash units — Electrical characteristics and test methods," strobe voltages up to 24V should be generally permitted. If Canon complies with the standard, then many questionable strobes, with trigger voltages ranging from 6V to 24V, should be considered quite safe with any Powershot camera. I'm now waiting for an answer from Canon about why they specify a much lower required value (so does Nikon, at 12V... maybe ISO 10330 is a "toothless" standard?). Canon's spec goes back a lot earlier than 1992, that much is certain... but any camera that complies with ISO 9000 should also comply with ISO 10330, and a gentleman from Canon Japan is the convener for that particular ISO working group..."

Here's what page 5 of the above master ISO/TC42 document says: "The TC goal is to facilitate the introduction of new technology to the marketplace through standards that define, measure, and specify electronic imaging. These standards are both supplier and consumer oriented. Suppliers require common test methods for specifying products. These common specifications allow consumers to understand product capabilities between manufacturers". Among the list of manufacturers on the same page 5 are Canon, Nikon, Konica/Minolta, Kodak as well as most imaging companies.

Anyone can download the above ISO 10330 international spec (now ~$65) and in it, it clearly establishes the limits (24V @ 100mA), the set-ups, and how each camera (from any manufacturers) is tested. The ISO 10330 makes no distinction between the hot-shoe or the sync terminal: My Metz is working fine with my 10D as well as other camera bodies thank you!


Now back to EE-101, and any designer out there can chime in, but I'm very rusty at this and can really hurt myself with a soldering iron: Is it true that an electronic switch can be as simple as a transistor (invented some 40 years ago), or an FET? Where the low side can be tied to ground (ie the camera case), while the high side (ie open-collector / open-drain) can be tied to any voltage (6V-24V sync terminal)? The current when this switch closes then can be limited by a simple resistor... The transistor's base can then be controlled from any low power microprocessor (1.8 to 3.3V) or Application Specific IC which they need to do anyway. So far this simple circuit easily meets the above ISO-10330 with only 2 parts costing less than a few pennies that any company will be fool not to!
One can get a little more fancy and use a higher priced device like KCan's above that can switch hundreds of volts, but still peanut on a $1000 camera!

... Oops I forgot one might need a diode to control the back EMF, but then that 24V protection Zener might do it too (Oh well I just added another penny!) :-) :-) :-)