First, test the lens stopped down at around f/8 or f/11. If images look sharper there, the issue may be shallow depth of field or slight focus error rather than a major optical fault. Stopping down increases depth of field, which can mask small focusing inaccuracies.

Next, check whether your camera offers AF micro-adjustment / micro-focus adjustment. If it does, fine-tuning autofocus can improve sharpness. If your camera doesn’t support that, a qualified camera technician can usually perform calibration.

If the lens still seems unsharp even after testing at smaller apertures and checking focus adjustment, a mechanical focus problem is possible, though that’s a less likely cause.

Before sending it for service, do a simple controlled test: use good light, a steady support, single-point autofocus, and compare wide-open versus stopped-down results. That will help determine whether it’s normal behavior, focus calibration, or a fault.