EOS 5D Mark IV has a Communication error with my 24-70 and won’t focus

[AshelyA02]

I have a canon 5D Mark Iv. I got an error 01: “Communication between lens and camera is faulty” with my 24-70 mm lens. I read to carefully clean the gold contacts with a lens cloth. I did and tried it again and got the same error. I tried a different lens and it connected fine, but on live view it only worked on MF. When I tried AF mode, it wouldn’t focus using the back button or the shutter button. I doubled checked all of my settings and everything is set where is should be, so I’m wondering if it’s both my lens and camera?

[p4pictures]

If you have another lens, or can borrow one then try that. If the other lens works with no error then it's your 24-70mm that is at fault. If the other lens you try gives the same error as your 24-70mm then it is possibly the body.

[AshelyA02]

Thank you for the response. The 24-70 mm lens had the Err 01. When I tried a different lens, it connected okay, but my camera wouldn’t focus at all on live viewing with any of my lenses.

[p4pictures]

Does the camera focus with the different lens when not using Live View? If so then it could be the Live View settings that are the cause. 

Check to see if you have continuous AF enabled, the constantly focuses the lens when in Live View even if no button is pressed. Also check the AF method form the Live View menus and check if you have disabled the shutter from activating AF with custom controls. 

[stevet1]

AshelyA02,

Does the touch screen focus work in Live View?

Steve Thomas

[AshelyA02]

Yes it does. I just can’t get my camera to focus on anything.

[deebatman316]

What is the FULL NAME of the EF 24-70mm lens you have. The F/2.8L version 1 had problems with the internal flex cable failing. Have you tried the AF-ON button to see if would AF.

[AshelyA02]

Yes, I also have the first version on the 24-70 mm 2.8 L. I have tried the AF on and still nothing. 😕

[deebatman316]

What does the aperture say. Does say an actual F/stop reading or does it say F/00 or F--. If the camera can't get an aperture reading. Then the flex cable has failed thus not allowing AF to work because the camera and lens can't communicate.