It means that the zoom control is literally a thing that you push or pull backwards or forwards, rather than being a ring that you turn. There is considerable noise in the system about push-pull lenses "sucking dust in like a vaccuum cleaner" but this is entirely an urban legend. The lens elements still move the same way regardless of how the user controls it. Most zoom lenses in the MF era were push-pull, and some of the legends of the AF period are too. The 35-70/f2.8 AFD is the most notable example.ultimind]...are there any disadvantages to this version vs. the two-ring model? I know the AF-S is leaps and bounds better[/quote] The big disadvantage compared to the two-ring is the lack of a tripod collar. (It's missing because there's no place on the push-pull that isn't part of the zoom/focus ring!) Compared to the AFS model said:I just curious what "Push/Pull" refers to, seen it alot but can figure it out.