One quick diagnostic: try focusing in Live View and compare to focusing through the viewfinder - if Live View nails it but the viewfinder misses you likely need AF fine‑tune (microadjust) or a shop calibration. Also check the little diopter wheel by the viewfinder so you’re not fooled by an out‑of‑adjustment eyepiece. For wiggly grandkids, stop down to around f/4–f/5.6 for a bit more depth of field, and if single‑point can’t keep up, try a dynamic/zone AF mode that tracks movement.
