Newer Rebel T7 hot shoe center pin

[DedTreeJig]

I just purchased a Rebel T7.  I know the original version did not have the center pin on the hot shoe, however mine does have the center pin.  Does anyone know if the center pin is active?  Would I be able to use a third-party flash with the camera?

[normadel · Accepted solution]

Where did you get your info?

A flash shoe without the center pin can't be a hot shoe. The center pin is the "hot" pin. Without it a flash can't be fired. So YES, your center pin is active and live.

You can use a third-party flash meant for Canons, though Canon doesn't recommend it. You can even use a manual  flash from the pre-digital days, if it has a trigger voltage no higher than 6 volts. There are varying opinions on how high a trigger voltage is dangerous for the camera, but 6 volts is safe.

[DedTreeJig]

Thanks for the information, I really appreciate it.

[jrhoffman75]

For clarity, do you have a T7 or a T7i? I haven't seen any info that Canon made a running change to the T7 and added the center pin. 

Even without the center pin the shoe is "hot" since it is powered with signal level voltage, but it will only fire Canon flashes.  A "cold shoe" is a flash shoe that will hold a flash unit but there is no signal to it. 

[normadel]

So the function of a center pin was moved to one of the other four little pins?  What Canon flashes can utilize this center-pin-less camera shoe? 

The whole idea sounds strange. Why would Canon do this?

[jrhoffman75]

 

[Lotus7]

"Why would Canon do this?"  Probably for exactly the same reason that Canon will not release electronic connectivity data for the RF Lens system to other lens manufacturers.  Have you checked the prices of current Canon flash units recently? 🙂

While changes in connectivity standards may bring increased functionality, they also can bring exclusivity and elimination of competition (at least for a while). As always, elimination of competition will almost always bring elevated profits.

[Bellmac]

I just purchased a refurbished T7 directly from Canon USA and it has a 5 metal contacts on the shoe, including the large flash trigger contact.

I am trying to get some documentation from Canon on maximum allowable voltage and/or current for flashes.  I have a couple of older Vivitar flash units.  On my Vivitar 6000AF macro flash (attaches to front of lens), the voltage is a maximum of 6VDC.  On my Vivitar 2800, the voltage is 45VDC.  I am much more interested in being able to use the 6000AC unit as it has 5 pins and is supposed to provide TTL flash control using camera settings.  The 2800 only has a single trigger contact and is a more basic unit, but does provide some automatic flash control.

I only used a multimeter to measure DC voltage.  A more thorough test would be to put it on a scope and see if there are any fast voltage and/or current spikes that the multimeter would not see.  Sometimes the spikes can do the damage.

I have not found any easy way to contact Canon technical support for some answers.  Any ideas would be appreciated.

I see there is a widely sold hot shoe electronic protector, but there is almost no real information available on the device.  It is a bit clunky to be stacking devices on the hot shoe and this device seems pretty over-priced and reviews seem mixed.

[MikeSowsun]

Modern Canon EOS cameras are safe for up to 250v. 

Your T7 has E-TTL and will not work with older film era TTL flash units like the Vivitar 6000.

The Vivitar 2800 is an older ”Thyristor” Auto flash with the light meter sensor on the front. It will work with your T7 but you will have to set the camera to Manual mode and then match the aperture and ISO to the Auto range selected on the flash.

[Bellmac]

Thanks for the quick answer Mike.  I am not surprised the TTL system in the Vivatar 6000 macro flash might not provide automatic control with the T7.  But where do you get the 250 volt number, which is often cited (6 volts used to be the cited value).  I cannot find any documentation from Canon.  Do you have an authoritative source?

Assuming 250 volts is the rating, what about peaks and current?  Any sense of the voltage and current peaks from older flash units.  I have some 120VAC studio flashes that I have not even considered yet.