FAQ - Aperture
How do I pan and zoom in ACM?
Use the plus and minus signs , shown above, to zoom in and out. You can also use the mousewheel on your mouse, or the plus and minus keys on your keyboard.
Once zoomed in, you can pan around by holding down the space bar and doing a click-and-drag on the image. This is done most efficiently if one is using a mouse. Simply zoom in, hold down the space bar, and click and drag the image to where you want it.