I’m using Lion with a new MacBook Pro. On my old Mac I used a mouse, so I’d down the Control key and use the scroll wheel to zoom in and out. I’m now using a trackpad, and can’t find that feature. How can I get it back?
The option you’re looking for is tucked away in Universal Access. Launch System Preferences, choose Universal Access, select the Seeing tab, and, in the Zoom area, click the Options button. At the bottom of the resulting sheet, you’ll see a Use Scroll Wheel With Modifier Keys To Zoom option, followed by the symbol for the Control key. (You can select that symbol and press a different modifier key to assign Cmd or Option to this shortcut.)
Don’t let the words Use Scroll Wheel dissuade you – this option will work with your trackpad. When you enable it, just hold down Control (or the modifier key you’ve assigned), and swipe up with two fingers on your trackpad to zoom in. Hold down that same key and swipe down to zoom out.