the Camera command (keyboard shortcut F6) will let you Show/Hide the camera in your viewports

• RMB = Right Mouse Button
• MMW = Middle Mouse Wheel

RMB or arrow keys

• To “break” a orthogonal view (such as your standard Top, Front, Right, etc.) and enter a tumble, use Ctrl + Shift + RMB

Shift + RMB

• In orthogonal views, RMB alone will do this

Ctrl + Alt + RMB

Shift + Alt + RMB

• In V4, doing this with the cursor at the edges of the viewport will constrain the rotation in 5 degree increments

Note: The target will not stay in the exact location, it will stay in the same plane perpendicular to the camera, however it's position on that plane will change depending where the cursor is located during the zoom

MMW

CTRL + RMB

• If you are using this method in a perspective viewport, you will find that as you zoom further and further in, you will eventually start to run into your target, which gives the appearance of not being able to zoom in any further. To correct this use Place Target

Rhino V3

• Shift + MMW

Rhino V4

• Alt + MMW
• Alt + RMB

Lens Zoom - Camera and target stationary, lens changed to zoom Alt + Shift + Ctrl + RMB