Camera hotkeys

Tumble, Track, or Dolly

Alt

Left mouse button

Tumble Tool (press and release)

Alt

Middle mouse button

Track Tool (press and release)

Alt

Right mouse button

Dolly Tool (press and release)

2D Pan/Zoom
\+

Middle mouse button

2D Pan tool
\+ Right mouse button 2D Zoom tool
\   Enable/disable 2D Pan/Zoom.