Last week I confessed that I have become an obnoxious Mac evangelist. A friend who is a Windows user was complaining that he'd misplaced his reading glasses and had to crank up the zoom in Microsoft Word so he could get work done. I commented that the Mac has this really great magnifier built in; it's become one of my favorite Mac features. He told me to go away. But the thing is, the Mac zoom really is a great feature. Let me tell you about it, and hopefully you won't tell me to go away.

I didn't think zoom would be useful for me when I first got my Mac in early February. After all, I thought, a magnifier is for the severely vision impaired, and my eyesight is better than 20-20 when I'm wearing my eyeglasses.

But I find I use the magnifier every day. It lets me compute comfortably.

I'm in the habit of rolling my desk chair backward and forward, through a distance of about 3 feet, all day and every day, to accommodate my various normal sitting positions. My normal working postures would make an orthopedist scream in horror and faint dead away. Sometimes I sit very close to the monitor, other times, I lean waaaaaaay back. I slouch.

Magnifying the display lets me see what I'm doing no matter what posture I'm sitting in.

To set it up, go into System Preferences, then choose Mouse. Down at the bottom there's a selection for "Zoom using scroll wheel while holding" -- select the checkbox next to it, then decide which modifier key you want to use to activate zoom. I have it set for the control key, you can also use the option key or Apple key.

There's an options setting that controls how the zoom behaves. I have it set so that the screen display scrolls left and right and up and down when the mouse pointer is near the edge of the screen. You can also set the display to scroll whenever you move the pointer or to keep the pointer centered and move the display around it, but I find those settings confusing.

Close out the settings boxes, and you're done.

Windows users can also zoom. The built-in zoom on Windows only enlarges a small segment of the screen. You can also find several utilities on the Web. I tried out several and preferred the free DesktopZoom.

DesktopZoom for Windows is not as simple as magnification on the Mac, and that's pretty much Windows vs. Mac all over: You can do the same things on Windows that you can do with the Mac, but it's simpler on the Mac.