When it comes to taking pictures on the go, it's hard to beat the convenience of a smartphone: It's lighter than a bulky SLR camera, and, unlike your typical point-and-shoot, it's in your pocket even when the idea of playing photographer is furthest from your mind.
This fact hasn't escaped the folks at Apple, who have worked hard over the last few years to turn the iPhone into the world's most widely-used camera by iterating through an increasingly sophisticated combination of hardware and software. This tradition continues with the iPhone 5s, which features some amazing new camera technology under the hood.
Bigger is better
Manufacturers just love to tout the resolution of their cameras; after all, more megapixels make for a great marketing pitch, and comparing numbers is easy for consumers to grasp. However, like megahertz on a CPU or inches on a TV, megapixels only tell a relatively small part of the story, and, after a certain number, they no longer help you take "better" pictures—only larger ones.
It isn't really a surprise, then, that Apple chose not to increase the 8MP resolution of the iPhone 5 camera when making the 5s. Instead, the company focused on other functionality that, while perhaps harder to explain, has the potential to allow the average user to take better pictures.
Perhaps the best example is the new camera's bigger sensor, whose surface is 15 percent larger than the one found in the iPhone 5. Because the number of pixels hasn't changed, this means that each of the photoreceptors on the phone can now capture more light—up to 33 percent more, according to Apple. Combine this with a new five-element lens, which sports a large f/2.2 aperture—an improvement over the iPhone 5 that should allow significantly more light to reach the sensor—and you end up with a camera that performs much better when shooting fast-moving subjects or working in low-light conditions.
MATT LASKOWSKI/FLICKR. A charge-coupled device (CCD)-the eye behind every modern digital camera.
The chip behind the scenes
The real magic of the camera of the iPhone 5s, however, is hidden away from its lens, tucked in a specialized portion of the A7 CPU called the Image Signal Processor (ISP). That's the hardware responsible for taking the raw input from the sensor and turning it into actual pictures. Rather than relying on third-party hardware, Apple introduced its own ISP with the debut of the iPhone 4s, and the company has been refining the chip's capabilities ever since.
With the iPhone 5s, the ISP has acquired some functions that you are much more likely to find in a high-end dedicated camera than in a smartphone. For example, in addition to attending to matters like white balance and exposure compensation, the chip uses a technique known as local tonal mapping to take individual portions of a photograph and independently enhance their contrast. If you take a shot of a dark subject against a very bright background, for example, the iPhone is capable of adjusting the latter so that it doesn't look washed out, while making the former lighter to increase its visibility.
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