Canon 5D Mark IV - Troubleshooting Flash, Remote Trigger, and AutoFocus

[SolomonShawn]

Hey everyone,

I'm attempting to troubleshoot an issue I'm having with flash and a remote trigger. I'm using the Canon 5D Mark IV.

While in live view, I am able to take a photo, but the flash will not trigger when taking a photo. If I switch live view off, the flash will trigger. Why is this? Is there a way to override this?

When I'm not in live view, and autofocus is enabled on my lens, my remote trigger is inconsistent. Sometimes it will take the shot, but other times it will simply autofocus, and won't take the shot. I can see it getting signal on the back of the camera, but don't know why it isn't firing.

If I switch my lens to manual focus, the trigger will fire the flash and take the photo every time. Any idea what might be causing this?

My flash is controlled by RF via a hot shoe mount, and the remote trigger is connected via the remote terminal port.

Any help is appreciated. Thank you!

[Nick2020]

Hi SolomonShawn,

Thanks for checking in with us!

There could be a couple of factors at work, so it would help to have some additional information.

• What flashes and triggering systems are you using?
• Are you also connecting to a computer, monitor, or mobile device?
• What shutter speed are you using?

We look forward to your reply.

[RobCPhoto]

I'm having a similar problem with my 5D Mk4. 

I'm shooting remote with and iPhone 8 running the Canon app over WiFi.  Live view.  Manual mode.  100-400mm Zoom Canon L lens on manual focus.   The flash works with a  Canon Speedlite 580.  But it doesn't fire with a KuangRen KX-800 macro twin lite.  The KX-800 has only one contact pin on its hot shoe.  It works fine in view-finder mode, but not in Live view.  Same thing without the iPhone and just using the shutter release.

[Waddizzle]

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@RobCPhoto wrote:

I'm having a similar problem with my 5D Mk4. 

I'm shooting remote with and iPhone 8 running the Canon app over WiFi.  Live view.  Manual mode.  100-400mm Zoom Canon L lens on manual focus.   The flash works with a  Canon Speedlite 580.  But it doesn't fire with a KuangRen KX-800 macro twin lite.  The KX-800 has only one contact pin on its hot shoe.  It works fine in view-finder mode, but not in Live view.  Same thing without the iPhone and just using the shutter release.

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Flash photography is [NOT] compatible with Live View.  The issue is that you cannot see what the final exposure would look like prior to firing the shutter.  The exposure isn't "correct" until the flash fires, so all you see is a mostly dark screen.

[RobCPhoto]

Then why does it work in Live View with a Canon Speedlite?  Both the Speedlite and the 5D Mk4 are in manual mode.

[Waddizzle]

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@RobCPhoto wrote:

Then why does it work in Live View with a Canon Speedlite?  Both the Speedlite and the 5D Mk4 are in manual mode.

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Oh, your issue is different from the original proble.  Probably should have started your own thread.

Why doesn''t your setup work with a third party unit?  I don't know.  I suggest that you ask the third party manufacturer why isn't their gear fully compatible with Canon gear.  Your best course of action is to stick to Canon Speedlights.