It’s been a while since I did this–I’ve been busy and have fallen behind–but here’s number three in the series on cool but little-known Mac features. It’s one I use a lot myself: the zoom feature. Not many people know about this one, because it’s tucked away under “Universal Access,” and you might think that you don’t need anything there unless you’re handicapped in one way or another; it is intended for Mac users who have vision problems. But the zoom feature has been a lifesaver for me.

My main use of the feature is in class. I teach some computer classes, and all I can show the students is what they see on the TV. Now, Macs are already very good about using a TV as a second monitor, either mirroring (showing the same thing on both screens), or with two separate but connected screens. The problem, however, is with resolution.

Computer monitors are like HDTV screens; in fact, my current screen is 1200 pixels tall, which makes it higher-def than a 1080p TV set, the highest-quality HDTV you can have right now. But when you show your computer to a class on a TV set, it’s suddenly low-def again–just 484 lines (the rest of the 525 lines in NTSC are used for other data). Plus, an NTSC screen is interlaced, which means that every time the TV screen “flashes” a frame, it’s really a half-frame–every other line, filled in by the other half of the lines 1/60th of a second later. Interlacing, along with the fewer lines of resolution, makes the text go fuzzy.

Add to that the fact that my students sit far from the TV and you get a situation where they cannot read a thing on the picture I show them–unless I zoom in. That’s where the zoom feature comes in handy for me, whenever I want to show more of the screen, with good enough clarity for everyone to see what’s going on.

Below is a movie I made (low-res, but you can get the idea) of zoom being used on my computer. I start out on this blog’s page, and use my standard setting, which zooms in double each time I press the F11 key (the original shortcut was Option-Command-+ and -, but I opted for a one-key solution). I then switch to the System Preferences, and demonstrate how you can set the feature to zoom a lot more hit a single keystroke–first 10x, then 20x, and then a more reasonable 4x. Hit another key (F12 for me) and it zooms out. The movie is in QuickTime format, 1.2 MB, 320×240 (it’s sharper than the preview image); click the image to see it in a pop-up window, or click here for it to take over this window.

It is ironic that I have to use my Mac to teach Windows to my classes, using Virtual PC. I’d love to use Parallels, but my laptop is a G4, so not yet. But I cannot use a Windows machine because the zoom feature in Windows sucks horribly. It divides the screen in half horizontally, with the bottom half being regular size, and the top half being zoomed. It is terribly distracting and confusing, as you’re not sure where to look. If you are used to the zoom in Windows, you’ll be blown away by the elegance and simplicity of zoom on the Mac.

One drawback: in Virtual PC, the zoom feature works (some Mac OS elements do), but it will not follow the cursor–instead, it stays locked in the center of the screen. It’s still functional, though. With Parallels, the Mac zoom works only if your mouse is outside the Windows environment, but it is similarly functional.

Not only is the zoom good for my classes, it’s also useful in daily use. My 24″ monitor is a monster, and often I feel much more comfortable zooming in to read small stuff, or narrow columns of text many blogs have.

If you have a Mac and want to turn the zoom feature on, you can use the keyboard shortcut Option-Command-8 to activate it, and then Option-Command-+ (plus) to zoom in, and Option-Command– (minus) to zoom out. To change these rather clumsy keyboard shortcuts, go to System Preferences, open “Keyboard & Mouse,” select the “Keyboard Shortcuts,” and change the “Zoom” settings under “Universal Access.”

You can also control the feature by going to System Preferences, opening “Universal Access,” and make sure that you’re in the “Seeing” tab.