As expected, Apple CEO Steve Jobs today unveiled the iPhone 4, with over 100 new features. Similar to the leaked prototype, the 9.3mm thick device—24% thinner than the iPhone 3GS—has aluminosilicate glass, chemically strengthened to be 30 times harder than plastic, on both the front and back with steel around the sides that also serves as part of the antenna system. As expected, its 3.5-inch display—which Apple is dubbing a “Retina display” due to its 326 pixel-per-inch pitch that’s above the limit of the human retina to differentiate the pixels—offers four times the resolution (960 x 640) of the current iPhone display, IPS technology, 78% of the pixels on the iPad, and an 800:1 contrast ratio, also four times that of the iPhone 3GS.
“iPhone 4 is the biggest leap since the original iPhone,” said Steve Jobs, Apple’s CEO. “FaceTime video calling sets a new standard for mobile communication, and our new Retina display is the highest resolution display ever in a phone, with text looking like it does on a fine printed page. We have been dreaming about both of these breakthroughs for decades.”

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The iPhone 4 is powered by the Apple A4 chip, the same chip found in the iPad. Thanks to the power management features of the A4, along with the larger battery, the iPhone 4 achieves 7 hours of 3G talk time, 6 hours of browsing over 3G, 10 hours of Wi-Fi use, 10 hours of video playback, 40 hours of music playback, and 300 hours of standby time. A gyroscope will be included in addition to the accelerometer for sensing rotation, pitch, roll, and yaw; enabling more accurate, six-axis motion sensing when used with the accelerometer.
A new camera system was developed for the iPhone 4, with a larger five-megapixel, backside illuminated sensor that keeps the sensor’s pixels the same size as on the iPhone 3GS while improving low light performance. The autofocus system keeps the same tap-to-focus interface of the iPhone 3GS, adding a 5x digital zoom, and an LED flash; the camera will shoot HD video at 720p at 30 fps, and will also allow for use of the LED while recording. In addition, videos will benefit from the enhanced editing capabilities of a new iMovie application for the iPhone, which will be $5 from the App Store.
Other iPhone 4 features include dual microphones for noise cancellation, a MicroSIM slot to allow for the larger battery, 802.11n Wi-Fi, and Quad-band HSDPA/HSUPA wireless, the latter standard not yet supported by most cellular carriers, but capable of increasing uploading and downloading performance.
The front-facing camera will work with a new feature called FaceTime video conferencing, which works from any iPhone 4 to any iPhone 4, anywhere there is Wi-Fi, with no setup required; it’s as simple as making a phone call. Callers can flip between the front or rear camera to let people see what they’re seeing in real time, and it works in portrait or landscape mode. Jobs said the company will work with cellular providers to offer the feature over cellular networks, but for 2010, the feature will be Wi-Fi only. The feature is based on H.264 with AAC audio, and Apple plans to offer the various components of the video calling technology feature as an open industry standard.
iPhone 4 will be available in white or black and with 16GB of storage for $199 or 32GB of storage for $299; any AT&T customer whose contract expires in 2010 will be eligible for the upgrade pricing.