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Canon EOS 10D, 30D trigger voltage clarification

Stefan Bruda , Nov 06, 2007; 01:57 p.m.


I have a flash that triggers at approximately 12V (measured, not from the specs), and I am wondering whether it is safe to use with the hotshoes of the mentioned EOSes. I have seen contradictory advice in these fora and elsewhere; indeed, some posts say that anything under 250V is fine on the PC connector and on the hotshoe too, others say that this is the case with 20D (and presumably the 30D) only while the 10D syncs safely at 6V and under only, and finally other posts say that the 6V limit is applicable to all the digital EOSes. I have written recently to Canon Canada and they replied quite confidently that the hotshoe trigger voltage limit for both the 10D and the 30D is 10V (this being the first time I hear the 10V variant).

In all, I am confused. I am then wondering whether anybody here has any direct experience with all of this. The 12V trigger voltage is very close to the Canon-claimed limit of 10V, so I am tempted to try it out. However, I obviously don't want to fry anything, so if anybody can shed some light (pun not intended) on the matter it would be appreciated.

Many thanks in advance.


Nathan Stiles , Nov 06, 2007; 02:24 p.m.

A hot shoe flash or a strobe?

Stefan Bruda , Nov 06, 2007; 02:53 p.m.

I am talking about a hot shoe flash (more specifically about a Vivitar 2500, whose trigger voltage seems to vary though mine is a bit under 12V).

Nadine Ohara - SF Bay Area/CA , Nov 06, 2007; 03:38 p.m.

I believe it has been verified by Chuck Westfall (an executive at Canon) that the 20/30/40D cameras sync voltage limit on both the hotshoe and PC socket is 250 volts. However, the 10D limit is still 6 volts. 12 volts is *probably* OK but you are taking a risk. I'd get a Safe Sync to be sure.

Stefan Bruda , Nov 10, 2007; 04:11 p.m.

Thank you, I have seen Chuck Westfall's comment. In the meantime I measured again the trigger voltage for good measure and it is in fact 10.55V, or 10V for all practical purposes (sorry for the earlier mistake). I conclude then that the flash is safe for the 30D.

I still have a great deal of doubts about the appropriateness of the flash for the 10D (Canon Canada says 10V, you are saying 6V). I was hoping to use it on the 10D as a backup flash (the 10D is a backup anyway), as I also have a Speedlite 550 for the main flash.

As for the Safe Sync, it is definitely a good idea, except that I want to go dirt cheap with the whole Vivitar 2500 setting (the flash itself is worth about $25). In any event, unless somebody knows positively that a 10.55V trigger voltage is safe for a 10D (if it is, please tell me) I will just ditch the whole thing.

Thank you for your answers.

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