> Zooming and Panning the Canvas
> You can zoom in and out on the canvas to view details or see the big picture.
> To zoom in or out on the canvas, hold down the Option Key and move the scroll wheel.
> You can also use these commands:

> • | Zoom in—select View > Zoom In (Command-=)

> • | Zoom out—select View > Zoom Out (Command--)

> • | Zoom to full pixel size—select View > Zoom to 100% (Option-Command-0 (zero))

> When the canvas is larger than the panel, scroll bars appear so that you can pan in any direction to view hidden portions of the canvas. Hold down the spacebar and drag to pan the canvas with a mouse.You can also use normal trackpad actions.