More and more DSLR cameras make it possible to calibrate or “micro-adjust” the focus of a lens to match a specific camera. This is especially important with telephoto lenses. You can do it yourself with your own home brew system and there are several commercial adjustment tools.
Datacolor SpyderLensCal SLC100
Focus Pyramid AutoFocus Lens Calibration Tool
DSLRKIT Lens Focus Calibration Tool
Page created November 21, 2017. Updated May 4, 2018.