Apple just fixed the biggest problem with smartphone cameras

Apple just announced the iPhone 7 camera and iPhone 7 Plus dual camera.

Both smartphones come with upgraded cameras, with the widest apertures we've ever seen on an iPhone, as well as machine-learning-assisted shooting. Apple's also made them a bit more appealing to hardcore photographers, with the ability to shoot raw DNG images like you can get from a DSLR (or some Androids). Raw files offer users finer control when they're editing, but are a bit technical for casual shooters and can't be uploaded straight to Instagram.

But there's a much bigger key difference between the two new Apple devices: The iPhone 7 has just one rear lens, like a normal smartphone, while the iPhone 7 Plus has a two-lens dual camera system.

Here's what you need to know about the cameras on the two new iPhones.

The iPhone 7 Plus' new telephoto lens is a big deal

This feature was a surprise.

Until now, the biggest problem with smartphone cameras has been that they're only wide-angle.

Wide angle is great for many things, like shooting landscapes, close-up action, or groups of people. But it only works (of course) up close, and tends to distort images of people.

For example, this image, taken on a smartphone, stretches and distorts its subject's face, making her look a bit cartoonish.

There's a sweet spot in the middle of the frame where the problem is less intense, but it can be tricky to hit:

By putting a long, 2x zoom telephoto lens on the iPhone, Apple's moved into the midrange perspective of 50mm DSLR lenses, a perfectly respectable focal length. In English, that means Apple built an iPhone that can actually shoot nice pictures of people.

No other dual-camera smartphone has this feature. I criticized the LG G5 earlier this year for instead pairing a wide lens with a wider lens. And the Huawei P9 has two lenses of the same length.

So expect some much more flattering portraits from the iPhone 7 Plus telephoto lens than we've ever seen from a smartphone.

Bokeh isn't new, but it's exciting

The iPhone 7 Plus will be many people's first encounter with a new technology called "computational photography," which uses data from multiple cameras working together to build richer, better images on smaller devices.

Computational photography has a few exciting possibilities, but the first and most obvious of these - and the only one on the iPhone 7 - is giving smartphone-sized cameras the ability to shoot with "bokeh." Bokeh is the word for that fuzzy background you're used to seeing in wide-aperture images from fancy DSLRs.

The iPhone 7 Plus, after a software update coming later this year, will be able use its binocular vision to introduce bokeh to the backgrounds of images. You can see an example Apple showed at the event above.

Apple isn't the first company to introduce this technology. Huawei included a similar feature on its dual-lensed P9, and even the 2015 Google Nexus phones could pull it off with some difficulty.

But neither of those technologies worked particularly well. The P9 can produce some nice bokeh, like in the image on the right, but often makes mistakes.

It seems likely given the company's history that Apple will produce a somewhat more polished version of the tech, though we'll have to wait and see.

Also, a two-lens computational photography camera can never approach the full potential of the technology. More complex devices, the 16-lens L16 from Light, may able to closely mimic DSLRs. But the iPhone 7 Plus's two lens system will likely only work in limited circumstances and within a limited distance.

The new iPhone camera might (finally) catch up with Samsung's world-beating Galaxy phones

The biggest problem with the iPhone 6s camera wasn't that it couldn't shoot artificial bokeh, it was that it was simply not as good a device as the Samsung Galaxy S7, which blew it out of the water on quality and specs.

The main reason: The iPhone 6s camera shoots at a relatively narrow aperture of f/2.2. Aperture is a measure of how wide a hole light has to pass through in the lens. Lower apertures mean less light gets in, lower quality, and worse images in low light. The Galaxy S7, S7 Edge, and Note 7 all use a f/1.7 camera - a much wider hole. (In aperture as in golf, lower numbers are better.)

But the iPhone 7 and 7 Plus rock f/1.8 lenses. That's close enough to the Galaxy to be within striking distance if the new iPhone sensor is good enough. We'll see which one wins out in a shoot-out, but it'll likely be close.