KOR lens in which only the internal lens group shifts during focusing. Thus, IF NIKKORS do not change in size during AF operation, allowing for compact, lightweight lenses capable of closer focusing distances. These lenses will be designated with the abbreviation IF on the lens barrel.nikongrossary
(Internal Focusing System)
Abbreviation for Internal Focusing
English abbreviation for Internal Focusing. Indicates that the focusing lens in the photographic lens is not an external lens. Owing to this solution, front and last lens elements do not shift or rotate, which is significant if filters or lens screens are used.