How does the magnifier work?
Even when you’re in Image Mode, you’re not really seeing your images at full size, unless they are relatively small. With today’s digital cameras, images are often many times larger than even the largest screens. What you see in Image Mode is generally a scaled version of your images, sized to fit into your review window. But sometimes you need to see the individual pixels of the full-resolution picture, particularly to check the sharpness of important areas of the photo; this is the purpose of the magnifier. Using it couldn’t be easier. You just turn it on (“Show Magnifier” in the Window menu, or use the keyboard control, which is bound to “/” by default), move it to the area you want to magnify (click-drag inside it), and there you are.