Matthew Panzarino:

Every time you take a picture with the iPhone 7, both the wide angle and telephoto fire off. Yes, two 12 megapixel pictures for every shot. This could be a prime driver behind the increase of the iPhone 7 Plus’ memory to 3GB.

Both images are needed due to an Apple technique it is calling “fusion” internally. Fusion takes data from both sensors and merges them into the best possible picture for every condition. If, for instance, there is a low-light scene that has some dark areas, the image-processing chip could choose to pick up some image data (pixels or other stuff like luminance) from the brighter f1.8 wide angle and mix it in with the data from the f2.8 telephoto, creating a composite image on the fly without any input from the user. This fusion technique is available to every shot coming from the camera, which means that the iPhone 7 Plus is mixing and matching data every time that trigger is tapped.

This technique is made possible because the optics, coatings, sensors, perspectives and color balances of the two cameras are perfectly matched.

The fusion technique also comes in handy when using the new zoom functions of the iPhone 7 Plus.

John Paczkowski:

A tentpole feature of the new iPhones are improved camera systems that are larger than the cameras in the devices that preceded them. The iPhone 7 now has the optical image stabilization feature previously reserved for its larger Plus siblings. And the iPhone 7 Plus has two complete camera systems side by side — one with a fixed wide-angle lens, the other with a 2x zoom telephoto lens. At the top of both devices is something called the “driver ledge” — a small printed circuit board that drives the iPhone’s display and its backlight. Historically, Apple placed it there to accommodate improvements in battery capacity, where it was out of the way. But according to Riccio, the driver ledge interfered with the iPhone 7 line’s new larger camera systems, so Apple moved the ledge lower in both devices. But there, it interfered with other components, particularly the audio jack.

So the company’s engineers tried removing the jack.

In doing so, they discovered a few things. First, it was easier to install the “Taptic Engine” that drives the iPhone 7’s new pressure-sensitive home button, which, like the trackpads on Apple’s latest MacBook, uses vibrating haptic sensations to simulate the feeling of a click — without actually clicking. [...]

Second, there was an unforeseen opportunity to increase battery life. So the battery in the iPhone 7 is 14% bigger than the one in its predecessor, and in the iPhone 7 Plus, it’s 5% bigger. In terms of real-world performance gains, that’s about an additional two hours and one hour, respectively. Not bad.

Even better, removing the audio jack also eliminated a key point of ingress that Riccio says helped the new iPhone finally meet the IP7 water resistance spec Apple has been after for years (resistant when immersed under 1 meter of water for 30 minutes).