When you need to select a small area for cropping, retouching, or red-eye reduction, it’s a good idea to zoom in on that area first to see your work in detail. You can also use the Zoom slider to change the size of thumbnails.
If you use Mac OS X Lion v10.7 or later on a computer with a trackpad or Magic Mouse, you can use Smart Zoom to toggle between zoom levels.
Zooming in or out does not affect the actual size of the photo (its dimensions or file size).
To zoom in or out when editing a photo:
Do any of the following:
Drag the Zoom slider at the bottom of the window.
To zoom in to the center of the photo, move your pointer off the photo, and then press 1 (to magnify 100 percent) or 2 (for 200 percent).
To zoom in to a specific part of the photo, move your pointer to the spot you want to look at, and then press 1 (to magnify 100 percent) or 2 (200 percent).
To zoom out, press 0.
To use Smart Zoom in Mac OS X Lion v10.7 or later:
Drag the zoom slider to the desired magnification.
Do one of the following:
If you use a trackpad, double-tap the trackpad with two fingers to toggle between your selected setting and full magnification.
If you use a Magic Mouse, double-tap the top of the Magic Mouse with one finger to toggle between your selected setting and full magnification.
When you zoom in on a photo, a small Navigation window opens. Drag the square in the Navigation window to view different parts of the zoomed image.