Conditions   All distance from closest lens vertex
Canon lens alone
Shot #   Distance  Notes
7           300mm     Focus MOD zoom full wide
8           same with diagonal ruler
9           400mm     Focus best zoom full wide
10         450mm     Focus best zoom full wide

Canon + Adapter
1          125.4mm   Focus MOD zoom full wide
4          225.4mm   Focus MOD zoom full wide
5          325.4mm   Focus MOD zoom full wide

Canon + adapter, zoom closed to not vignette
2          125.4mm   Focus MOD zoom no vig.
3          225.4mm   Focus MOD zoom no vig.
6          325.4mm   Focus MOD zoom no vig.