I had it checked in case it needed repair, but they said they could not find a problem with it. I really need help on this one.
[the process]
I turn the camera on, select M mode, select the top focus point in auto-focus, it turns red when I press the button to make a photo, but when I look at the bottom part it's clear. It obviously focuses on that part.
I also tried the manual focus, but the result is the same.
[lens]
I tried with two different lens that were checked recently and are in perfect condition. I could upload an image I suppose.