Today is a big day for anyone who’s managed to get their hands on an iPhone 7 Plus—not an easy task, considering how few are available to buy.

Because today, you can turn on Portrait mode.

First, some background: The 7 Plus has two camera lenses: one wider angle, one a 2X zoom. Clever software lets you blend the zoom to any degree between them (or, using digital zooming, go all the way up to 10X).

But when Apple (AAPL) introduced the 7 Plus, it said that the two-lens setup has a second benefit: It lets the camera tell the foreground subject apart from its background.

And with that knowledge, the phone can create a soft blurry-background look, as in this shot (of fellow Yahoo employee Marissa Weber).

(Some photographers refer to this blurriness as bokeh, although technically, that word describes the quality of the blurriness, not the blurriness itself. “I love the bokeh this lens gives you,” you might hear.)

Ordinarily, you see that look only in professional photos, or at least photos taken with big black SLR cameras using high-aperture lenses (f/1.8, for example). Like these:

But soon, Apple said last month—once it finished writing the software—you’ll be able to do that with your phone.

Today’s the day. You can download the iOS 10.1 update for your iPhone 7 Plus that gives it a beta version of the new Portrait mode. (Open Settings -> General -> Software Update, and click Install.)

Now, the blur in this case is not optical, the way an SLR makes it. This is a glorified Photoshop filter; it’s created with software.

And Apple’s not the first company to try it. Some Samsung phones, years ago, offered a similar feature. But without dual lenses, those phones didn’t have great luck distinguishing the subject from its background, and you often wound up with hideous “leaking” of the blurriness effect.

Apple’s effect on the other hand, generally looks great, even when the outline of the subject is complex (like frizzy hair). The blur occasionally looks a little phony, as in the building outlines shown here, but at least it never spills out into your beloved’s face. (It does occasionally leak into non-human subjects. Maybe that’s why this feature is still called beta.)

How to use Portrait mode

The new feature shows up as one of the modes in the Camera app—you know, VIDEO, PHOTO, SLO-MO, and so on. Now there’s PORTRAIT.

Point the camera at someone who’s standing between 15 inches and 8 feet away, and boom: You see the background blur, right there in the preview image, as shown in the video above. Take the shot. That’s all there is to it.

If a second person is standing within the 8-foot range, you can tap the screen to make that person the subject.

In Settings -> Photos & Camera, you can turn on “Keep Normal Photos” for this depth effect. It means, “For each Portrait photo I take, save two images—one with, and one without the blur.”

Fine print on Portrait mode

Portrait mode doesn’t always work. It can get confused when:

• The light is dim, like in a bar or restaurant in the evening.

• The subject is covered with a repeating pattern.

• Your subject is reflective, like a shiny bottle.

• Your subject is farther away than 8 feet, or closer than 15 inches.

As long as the light and the distance are right, though, the results are surprisingly good. Everyone I showed the results to was fairly amazed; the shots look exactly like fancy SLR shots.

Soon, the Flickrs (YHOO) and Facebooks (FB) of the world will start teeming with great-looking, blurry-background photos—or at least they will once Apple starts making enough iPhone 7 Pluses to sell!

David Pogue, tech columnist for Yahoo Finance, welcomes non-toxic comments in the Comments below. On the Web, he’s davidpogue.com. On Twitter, he’s @pogue. On email, he’s [email protected]. Here’s how to get his columns by email.