Nikon D IF lens Help

[Bronikon]

Hi all , I have a feeling Im about to ask a question with a very obvious answer well what the hell here goes can anyone tell me what the IF stands for on the D type lens.

If this is in fact a dumb question my excuse is this on sunday I was out in the wilds taking pics , lost car keys to which was attached house keys got home eventually to find out central heating knackered , then realised i had stupidly left my tripod on the hill.

Anyone recomend the appropriate tablets.

 

[Dogfish_magnet]

Internal focus - the end element doest move while focusing.

from nikon site

Internal Focusing. A conventional double helicoid focusing system requires that all lens groups be moved by the lens barrel to either the front or rear during focusing. This mechanism is not only complicated but bulky, more so in the case of telephoto lenses where the extra physical length of the lens requires the use of a heavier gauge metal with a consequent increase in size and weight. In addition, a change in the length of the lens when focusing results in unbalanced hand held shooting.

To remedy this situation, Nikon developed the Internal Focusing (IF) system. With IF, only the internal small lens group shifts during focusing with no change in the lens' physical length, permitting more compact, lightweight construction and a closer minimum focusing distance for telephoto lenses. Additional benefits include faster focusing and a reduced diameter of the focusing ring due to a simplified focusing mechanism.

 

[Bronikon]

Thanks Dogfish for the swift answer sounds good to me .
Now all I need is the bloody Heating Engineer to finish the job and get warmed up.

Guid Health