Zoom assembly having zoom lens with plurality of lens group that move together or differentially for zooming and focusing

A zoom assembly comprising:

• a zoom lens defining an optical axis, said zoom lens being capable of operating in a plurality of different zoom positions and of focus adjustment for different object distances in each of said zoom positions, said zoom positions being two extreme zoom positions comprising a wide position and a telephoto position, and a plurality of intermediate zoom positions, said zoom lens including at least a first movable lens group and a second movable lens group, said first and said second lens group being separated from one another by a variable distance, wherein said first and second lens groups move
• (a) together, at the same speed and direction to focus at the wide angle position;
• (b) differentially, to transition from the wide angle position to a first intermediate zoom position;
• (c) together, at the same speed and direction to focus at the first intermediate zoom position;
• (d) differentially, to transition from said first intermediate zoom position to a second intermediate zoom position;
• (e) together, to focus at said second intermediate zoom position;
• (f) differentially, to focus at a third intermediate zoom position;
• (g) differentially, to focus at a zoom position adjacent to said third intermediate zoom position.