topic Re: Canon speed lights not connecting with my Canon 5D MIV in Speedlite Flashes

Canon Speedlite units not connecting with my EOS 5D Mark IV

julienmcroberts — Tue, 04 Feb 2025 14:54:56 GMT

Hello

Gear: Canon 5D MIV
Strobe: 600 EX-RT and 580EX II
Wireless Transmitter: ST-E2
I just got my main gear after it being in storage for a year and the camera has been working fine however I went to use my strobe and it is not connecting. I thought it was the flash batteries but I have a brand new charger and fresh batteries. When I turn on the strobe(s) (not connected to the camera) nothing lights up. When they are connected to the hot shoe, nothing lights up either and they are not firing. The regular Canon batteries are fully charged although the batteries and a few years old but this was not an issue when I last used the strobe before the gear went into storage. Flash is enabled in the menu setting.

I thought it may be the hot shoe not working on the camera but it is connecting with the wireless transmitter.
Any thoughts on this? Any help is appreciated.

We just moved to Paris and I need to get this fixes ASAP and will have to look into where I can get this done as I have upcoming shoots.

Re: Canon speed lights not connecting with my Canon 5D MIV

p4pictures — Sun, 02 Feb 2025 12:06:08 GMT

Check inside the battery compartment to make sure all the connections are free from corrosion. Also try a set of AA alkaline batteries in the Speedlites. You can get them in many stores. This is just to make sure it’s not the rechargeable batteries that are the problem.

Re: Canon speed lights not connecting with my Canon 5D MIV

deebatman316 — Sun, 02 Feb 2025 13:39:18 GMT

My 600EX II-RT doesn’t play nicely with rechargeable batteries for some reason. I found that you have to use alkaline batteries. I guess it’s the voltage difference between them. But my other flashes work fine. Can you even access the 600EX II-RT settings from the external speedlite control menu. The same should be true for the 580EX II. Does modeling flash even work at all.

Re: Canon speed lights not connecting with my Canon 5D MIV

p4pictures — Sun, 02 Feb 2025 15:01:07 GMT

That's interesting to hear about the incompatibility with rechargeable batteries. I've all but exclusively used my 600EX-RT and 600EX II-RT units with Eneloop and Eneloop Pro rechargeable batteries since I've had them.

Re: Canon speed lights not connecting with my Canon 5D MIV

deebatman316 — Sun, 02 Feb 2025 15:38:00 GMT

Rechargeable AA batteries put out 1.2 Volts DC and Alkaline batteries put out 1.6 Volts DC. The flash will often read rechargeable batteries as dead. Due to the lower voltage. My old 550EX works perfectly fine with them and never displays the dead battery icon.

Re: Canon speed lights not connecting with my Canon 5D MIV

julienmcroberts — Sun, 02 Feb 2025 16:23:21 GMT

Like you, I have exclusively used rechargeable batteries for years with no problem so I doubt that is the issue. It appears to be an issue with both flashes and thankfully not the hot shoe.

Re: Canon speed lights not connecting with my Canon 5D MIV

deebatman316 — Sun, 02 Feb 2025 16:29:29 GMT

Does modeling flash fire when the speedlite is mounted to the camera. By default pressing the depth of field preview button will make the flash fire the modeling flash. Have you tried the flash on a different camera.

Re: Canon speed lights not connecting with my Canon 5D MIV

julienmcroberts — Sun, 02 Feb 2025 16:35:38 GMT

Hi
Nothing lights up at all with either flash when mounted on the camera or with the wireless and also with pocket wizzards. After playing around with it, it appears to be an issue with the flashes but both??? They were sitting in storage for a year but not sure how that would affect them.
No corrosion on any of the items.

Re: Canon speed lights not connecting with my Canon 5D MIV

deebatman316 — Sun, 02 Feb 2025 16:59:20 GMT

Can you test the flashes on a different camera. It’s unlikely to have 2 flashes not working on the same camera.

Re: Canon speed lights not connecting with my Canon 5D MIV

deebatman316 — Sun, 02 Feb 2025 17:17:01 GMT

Take a picture of both flash units while on. In wireless mode both flashes can be set not to fire but tell the other off camera flashes to fire.