Zoom tool

To zoom in on an image, either click with the zoom tool to magnify, or drag with the zoom tool, marqueeing the area you wish to zoom in to (but see the section below on the default selection of the Scrubby Zoom option). An image can be viewed anywhere between 0.5% and 1600% magnification and in normal mode, a plus icon will appear inside the magnifying glass icon. To zoom out, hold down Option/Alt and click (the plus sign is now replaced with a minus sign).

Note that when any other tool is active (apart from the type tool), holding down the Spacebar + the Command/Control key will call up the zoom tool and holding down the Spacebar+Option/Alt will call up the zoom out tool. Another useful zoom shortcut is to use Command/Control + the plus key (+), (which is effectively the = key). This allows you to zoom in and use Command/Control + the minus key (the one next to the = key), which allows you to zoom out. The zoom tool also has some other hidden functions. If you double-click on the zoom tool, this will magnify the image to 100%. But there are also some navigation options buttons in the zoom tool options bar. So for example, you can click on ‘Actual Pixels’ to magnify the image to a 100% scaled view (the same as double-clicking the zoom tool). You can click on the ‘Fit Screen’ button to make the document fit to screen, or click on ‘Print Size’, which resizes the image to approximate the size of the image when it is printed. Remember, you can also set the zoom level via the View menu, the lower left box of the image document window, as well as via the Navigator panel.

Checking the Resize Windows to Fit box will cause Photoshop document windows to always resize to accommodate resizing, but within the constraints of the free screen area space.

If OpenGL is enabled ‘Scrubby Zoom’ will be checked by default in the zoom tool Options bar (see Figure 1 below). This overrides the marquee zoom behavior – dragging to the right zooms in and dragging to the left zooms out.

Figure 1 The zoom tool Options bar.

Scroll wheel zooming

If your mouse or pen stylus features a scroll wheel then you can use this in Photoshop to scroll and zoom the image (but you'll need to go to the Photoshop General Preferences first and check the Zoom with Scroll Wheel box). With this option enabled, you can use the scroll wheel to scroll the image (on a Mac system at least, the might mouse will allow you to scroll horizontally and vertically). Hold down the Option/Alt key to access the zoom and use the scroll wheel to zoom in and out. If you hold down the Shift key as you operate the scroll wheel you can constrain the zoom to the usual fixed percentages.