Hi Bozi,

Thanks! Robert Rottmerhusen explains why 3rd party manufacturers are changing the LensIDNumber in their lenses:

"The reason why the 3rd party manufacturers are using different ID's now is the focus adjustment feature of newer Nikon pro cameras. This feature uses only the one byte LensID to recognize a lens (again) and this was almost one number in the past with these lenses."

So the reason is to differentiate their lenses for the new focus adjustment feature.

- Phil