I've got a Nikon D7500 with the AF-S DX 18-300mm zoom, a combination I love. I do a lot of outdoor photography and find myself switching between wide angle and telephoto repeatedly as different shots present themselves; for a while I switched lenses when this happened but switching lenses in the outdoors is a bit risky/dirty.
The problem that I'm having, is that my eye's auto-focus isn't working, so I rely heavily on the camera's auto-focus, and it's not really 100%. Both the lens and the body are set to auto-focus, and I can clearly see in the lens the rectangles as it decides which objects in the shot it's going to focus on, and I can hear the motors working, and see the focus shifting, and in the viewfinder it looks like it's dead on - but then in the resulting picture the focus is just a tiny bit off in about 1/3 of the shots. The problem is the most noticeable when at full telephoto (300 mm).
Am I expecting too much? Is auto-focus just not going to work well with this lens at full extension? Or is this something I should take the camera/lens into the shop for a tuneup?