Last week my two-year-old 80D started having focusing issues when I use the viewfinder. When using LiveView, it works fine, but when I use the viewfined, even though it shows green squares, the focus points come out blurry in the pictures. Tried differen lenses (70-200 2.8, 85 1.8, Sigma 50 Art), and all show the same problem (lenses work fine on my 6D Mark 2). Tried with auto and manual modes, same story. I installed the latest firmware, but it did not help. Any ideas what could have cause it and what I can do? I did not have any accidents with the camera (no drops, water, etc, so I am really puszzled). Thanks.
Could it be something a local camera repair shop can fix or does it need to go to Canon?
If a rocket blower cleaning did not fix it, then you should contact Canon Support.
You only want a factory authorized service center to repair your camera, whenever possible. Some local camera stores will simply handle the paperwork and shipping to and from an authorized Canon Repair Center, which is fine in my book.