EOS 5D Mark IV error with EF 28-300mm lens, other lenses OK

[orthodan]

I have had a Canon EF 28-300 f3.5-5.6 L IS USM for many years.  My Canon 7D started having problems so I bought a used low mileage Canon 5D Mk IV from a friend when he went mirrorless.  After a few shots, I get the error message about difficulty communicating with the lens - clean the contacts.  I have thoroughly cleaned the contacts with no benefit.  If I turn the camera off, then on, it works for a while then the error recurs.  Sometimes it is 3 or 4 images, sometimes 20.  I don't have the same problem with any other lens, and I don't have the problem with the 7D body.  Is this a firmware problem or a compatibility problem, or is the lens getting old.  If I am looking through the viewfinder in manual mode, I notice that there is a metering problem with the image where I get the error message.

[shadowsports]

Greetings,

What is the error message?  Err70, 80?  Does it happen with any other lenses? 

Are you using any accessories?   

Since the camera was used, have you tried resetting the camera, testing with different storage media and a new battery?  Its too soon to say if its body or lens at this point.

[orthodan]

error 001  it doesn't happen with any other lens, and does not happen with my 7D.  Only accessory is cable release.  Storage media and battery are not the problem.

[deebatman316]

Test without the shutter release cable. If it continues to happen without it. Set the camera to Av Mode and set a small aperture such as F/16. Then press the depth of field preview button. The view finder should significantly darken. If it doesn’t it could be a bad flex cable in the lens. I would press the depth of field preview button multiple times. To simulate a picture being taken. The aperture stays wide open until the picture is taken. This allows the viewfinder to be as bright as possible. I would also zoom the lens in and out too. Years of zooming in and out often times causes flex cable issues.

[orthodan]

When I use my EF 400L and 1.4x extender with the 5D Mk IV and the cable release, it works fine, so I don't think it is the cable release.  I will try the DOF preview.

[orthodan]

I pressed the DOF button at least 50 times with no problem.  1st photo, got error message 001. No cable release.f16 

[deebatman316]

When the communication error occurs can the camera still report the F/ stop. If the camera reports F/— or F/00. The camera doesn’t know that a lens is attached. The camera uses the electronic contacts to detect whether a lens is mounted or not. 

[orthodan]

Inside the viewfinder it just reports error.  LCD screen shows error 001.  No other data

[deebatman316]

This is a lens communication problem. Does the lens work on a different camera to rule out the lens.

[orthodan]

the lens works fine on my 7D