Please post some samples and be sure the EXIF is visible. If not, please include the EXIF with each photo. That's the only way we can truly tell if something is wrong with your camera, your settings, or if it's something else.
As others mentioned, make sure you have the latest firmware for your lens. If it doesn't have the latest firmware, the communication between the body and lens might be compromised.
As others mentioned, make sure you have the latest firmware for your lens. If it doesn't have the latest firmware, the communication between the body and lens might be compromised.