EOS 5D Mark IV struggles to autofocus with 85mm Sigma Art

[Pasar]

Hi! I just bought 85mm Sigma art lens to use with my EOS 5D Mark IV unfortunately am struggling to use Autofocus option, sometimes AF works fine sometimes it doesn’t. I sent back the lens to where i bought for testing they told me the lens has no problem, i tried it with other cameras it seems to work just fine, so i dont know what might be the problem because my camera works fine with other lenses. Kindly need assistance thanks

[shadowsports]

Greetings,

Having owned several Sigma Global Vision lenses, my first question might be what version firmware is your lens running? 

Ensuring your Canon body is running the latest firmware available is also recommended.  

I've used many Sigma lenses over the years with canon bodies and have never had an issue.  Is there a reason why you didn't buy a Canon lens to use with your Canon body?

Typically we would recommend resetting the cameras main and custom settings to default, then retesting without making any changes.  

I hope you have some recourse with the store where you purchased.

[stevet1]

Pesar,

You might not be alone.

Do a Google search for, "Is the 85mm Sigma art lens compatible with my 5D mark 4?"

The results may surprise you.

Steve Thomas