Set the camera to focus-priority release, Custom Settings a1 and a2.

Remove the focus control from the shutter button, either by using manual focus or ae-L button focus (Custom Setting f5).

Prefocus on the desired spot, press and hold the shutter release, wait for something to become in focus.

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Joseph K
Seattle, WA, USA

D700, D200, D70S, 24-70mm f/2.8, VR 70-200mm f/2.8 II, 50mm f/1.4 D,
17-55mm f/2.8 DX, 70-300mm f/4.5-5.6 VR, 18-70mm f/3.5-4.5 DX