This question is about Nikon SLR terminology. The answer could be different for non-SLR cameras, or for different maker.
The "minimum focusing distance" in the spec — it's measured and listed between what and the subject? Between sensor and the subject? Or between front of the lens and the subject? Or between back of the lens and the subject? At close distances and large lenses sizes, this makes big difference ...
The mystery comes from a review of the 60mm AF-S Micro Nikkor lens by Ken Rockwell. Ken is very trustful and thorough reviewer. In the "spec" section, Ken lists 18.5cm as "minimum focusing distance" (close focus)". No surprise, 18.5 cm is what appears in all published specs.
But Ken apparently owns this lens. Under title "Working distance" he pictures the Nikon and teddy bear, the subject, just several centimeters in front of the lens. He writes: "Nikon 60mm AF-S at closest focus distance... I measure only ... 48mm between the front of the lens and the subject at the closest focus distance"
Hmmm. It was 18.5 cm just several paragraphs above. Now it is 4.8 cm? Can anybody explain the discrepancy ? And answer my question at the beginning?