Apple has announced the iPhone 6 and iPhone 6 Plus featuring 4.7-inch and 5.5-inch Retina HD displays. The new iPhones feature a unibody enclosure of anodized aluminum.

The iPhone 6 and iPhone 6 Plus feature Apple's A8 chip with second-generation 64-bit desktop-class architecture for performance and power efficiency; iSight and FaceTime HD cameras; wireless technologies; and Apple Pay. Both models include iOS 8, the latest version of Apple's mobile operating system, featuring new Messages and Photos features, QuickType keyboard, a new Health app, Family Sharing and iCloud Drive.

The iPhone 6 features a 4.7-inch Retina HD display with 1,334 by 750 resolution, providing 38% more viewing area than the iPhone 5s, while the iPhone 6 Plus features a 5.5-inch Retina HD display with 1,920 by 1,080 resolution, providing 88% more viewing area and nearly three times the pixels than iPhone 5s. The Retina HD displays offer advanced technologies including higher contrast for deeper blacks and dual-domain pixels for more accurate colors at wider viewing angles, the vendor said.

With Metal, a new graphics technology in iOS 8, developers can take performance of the A8 chip to bring console-class 3D games to iPhone. The A8 chip also includes a new Apple-designed image signal processor that enables advanced camera and video features.

Both models include the M8 motion coprocessor that gathers motion data from the accelerometer, gyroscope, compass and the new barometer, which senses air pressure to provide relative elevation. The M8 motion coprocessor can continuously measure the user's motion data. With iOS 8, motion data from M8 appears in the Health app so users can see how many flights of stairs they have climbed, or how far they have walked or run. Developers can use CoreMotion APIs that take advantage of M8 and HealthKit to create apps that help users take better care of their health and fitness.

The iPhone 6 and iPhone 6 Plus introduce Apple Pay, which allows users to pay for physical goods and services in stores or apps. Users can pay securely and conveniently in stores by simply holding the phone near the contactless reader while keeping a finger on Touch ID; there is no need to unlock your iPhone or launch an app. With Apple Pay, the user can also make one-touch purchases within apps, without having to enter credit card or shipping information. All payment information is kept private, encrypted and stored securely in the Secure Element, a chip inside the new iPhones.

The iSight camera is equipped with a new sensor featuring Focus Pixels for faster autofocus. iPhone 6 Plus users will also benefit from optical image stabilization technology that compensates for hand shake in low light and works with iOS 8 to reduce subject motion. High-definition video on iPhone improves with faster frame rates up to 60fps for 1080p video and 240fps for slo-mo, as well as continuous autofocus, cinematic video stabilization and time-lapse video. The FaceTime HD camera now captures over 80% more light with a new sensor, larger f/2.2 aperture and advanced new features including burst mode and HDR video.

With LTE download speeds of up to 150 Mbps, iPhone 6 and iPhone 6 Plus users can browse, download and stream content faster. The new iPhones also support high-quality voice calls over LTE (VoLTE) as well as Wi-Fi calling. Both iPhones also include 802.11ac Wi-Fi with speeds up to 433 Mbps and Bluetooth 4.0.

The new iPhones come with iOS 8, which has new features including QuickType keyboard, a new Health app, Family Sharing and iCloud Drive. With more than 4,000 new APIs, iOS 8 allows developers to further customize the user experience with major extensibility features and frameworks such as HealthKit and HomeKit.

The iPhone 6 comes in gold, silver or gray, and will be available in the US for a suggested retail price of US$199 for the 16GB model, US$299 for the 64GB model and, a new 128GB model for US$399 with a two-year contract. The iPhone 6 Plus comes in gold, silver or gray, and will be available in the US for a suggested retail price of US$299 for the 16GB model, US$399 for the 64GB model and US$499 for the 128GB model with a two-year contract. Both models will be available from the Apple Online Store, Apple's retail stores, and through AT&T, Sprint, T-Mobile, Verizon Wireless, additional carriers and select Apple Authorized Resellers. The iPhone 6 and iPhone 6 Plus will be available in the US, Australia, Canada, France, Germany, Hong Kong, Japan, Puerto Rico, Singapore and the UK beginning on September 19.

Apple-designed leather cases will be available in black, pink, olive brown, blue and red for US$45 for iPhone 6 and US$49 for iPhone 6 Plus and silicone cases in black, blue, pink, green, white and red for a suggested retail price of US$35 for iPhone 6 and US$39 for iPhone 6 Plus.

The iPhone 5s will be available in the US for a suggested retail price of US$99 for the 16GB model and US$149 for the 32GB model, and an iPhone 5c 8GB model will be available for free. iOS 8 will be available as a free software update starting on September 17. Apple Pay will be available to US customers as a free software update to iOS 8 this October.