How to check if Nikkor lens has IF feature?

Question

The specification for the lens says that the Nikkor 18-105mm ED VR has the IF feature. However, the local market product label doesn't advertise this feature. How can I make sure that the IF feature is there? Is it possible that Nikon has the same lens with and without the IF feature?

Strange enough Nikon itself does not advertise the IF feature in the product label as I would usually see (IF-ED).

Answer

The "IF" is included on the lens (see image here on Ken Rockwell's site): 18-105mm specifications

The lens will extend when you zoom. IF (in this instance) appears only to mean that once you set a focal point, say 105mm, as you focus the outer part of the lens won't move. So if you have a polarising filter on, it won't turn as you focus.

Edit: just read the PHotozone review which basically says what I said above. Lens will extend as you zoom, but not rotate as you focus. Quite different than lenses which do not extend/rotate as they zoom OR focus.

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