Nikon D Series Fine Focus Adjustment Guide

This comprehensive technical guide walks you through fine autofocus adjustment on Nikon D-series digital cameras, using the D70 as the primary example with procedures applicable to other models in the lineup. The workshop manual covers the complete adjustment workflow—camera setup, mirror locking techniques, and the precise insertion of an Allen key into the AF mirror adjustment screw. You'll find detailed step-by-step instructions on rotating the AF mirror adjustment screw to shift the autofocus point closer to or farther from the camera body, along with labeled diagrams of the mirror box assembly showing the image sensor, focusing screen, mirror, and AF mirror adjustment mechanism. The guide includes critical handling notes to protect the shutter mechanism positioned near the adjustment screw. A reference image comparison methodology helps you objectively evaluate whether focus accuracy has improved or degraded after adjustment. Particularly useful for users working with modified infrared cameras that require precise autofocus calibration, this repair guide assumes familiarity with internal camera mechanics and provides the technical depth needed for accurate, confident adjustment work.