gordon_blackler

Thanks for your detailed response, Mark. The camera is still under warranty so I can (and probably will) send it back to the camera shop that sold it to me. It was an online purchase. There is no Canon dealer in my city unfortunately. So, I'll try to explain what I mean by the camera freezes: It's actually very erratic. Sometimes the button does nothing for several presses. Same on the grip. Most often though, in ONE SHOT mode, when I'm looking through the viewfinder and I press the AF-ON button, the AF word appears in the bottom right corner and won't go out. Focusing gets stuck. I have to press the AF-ON button several times to unstick it. Sometimes the only way to cancel AF is to turn the camera off. Sometimes I can take a picture, sometimes not. When I have AI SERVO selected and press the AF-ON button it also gets stuck and keeps hunting / trying to focus if I move the camera around. Again, sometimes another press of the AF-ON button will cancel it, sometimes it takes several times and sometimes I can / can't take a photo. This is all before I take a picture, so the memory card is not even in the equation yet. I've tried with the grip attached and also not attached. I've also tried with the grip attached but turned off. No difference in any scenario. If I assign AF & Metering to, for example the asterisk button (usually for AE lock), AF works fine, so the problem is always the AF-On button on the camera and grip. Does that make sense? Thanks.

Hi Mark, After more time testing, I can answer your questions as follows: • I have Canon and Tamron lenses. Doesn't make any difference. • I'm not using any third party attachments. I have an original Canon grip. The AF-ON issues happens on the body AND on the grip. • I'm using fast Sandisk cards - fast enough for 4k video. • I have Canon and Tamron lenses. Doesn't make any difference. • It happens in all modes except full auto (because you can't assign AF-ON in that mode - there's no access to the "Q" functionality. Update: 6th Sept, 2019 AF-ON button is malfunctioning on the body and grip for all modes I set it to, not just focusing. There is nothing physically wrong with the buttons on the camera or grip so I don't know if it's a firmware bug or some other fault with the electronics. Yesterday I tried to re-install firmware 1.1.2 but it didn't help.

I have a 5D mark IV running firmware 1.1.2 with about 1 year left on the warranty. The AF-ON functionality has recently started behaving strangely, without me changing any settings on the camera. It started during an event when the AF-ON button wouldn't focus (I use back button focus and set the shutter to only meter and take the photo). The camera started to lag for several seconds or freeze up entirely and I couldn't take any more photos unless I switched it off then on again. After further testing, I see that no matter what function I assign to the AF-ON button, pressing it causes that function to stick and freeze up the camera. If I assign focus, when I press the button, the AF stays on and won't cancel when I release the button. Or if I assign metering to the button, the camera freezes up immediately. If I assign those functions to other buttons, for example if I assign focus to the "*" button next to it, all is ok. It doesn't matter which lens I use, whether the grip is attached to the body or not, or which type of battery I use. The problem happens with all or any of those combinations. A couple of last points to note. - Sometimes the freeze can be undone by half pressing the shutter button. Usually the AF-ON function is cancelled successfully by taking a photo. - It doesn't always happen. The problem sometimes only happens for a few photos and then it's fine. Then it comes back again. Do you think I should simply send the camera back to the shop or have I missed a setting somewhere? Thanks

I have discovered a different problem with my Videomic Pro. I get a horrible interference when I switch on the camera's wi-fi. It sounds like crackling, popping, tapping and sometimes like a low-fi explosion from an old 8-bit games console (Atari, etc). Has anyone else experienced that and found a fix?