UPDATE: We strongly recommend reading our update to this review, which was written after using the iPhone 4 for after one month. It details some of our issues regarding the antenna/cell reception and the proximity sensor.

The all-new iPhone 4's release date is set for June 24th, but we've decided to take a look at the new iPhone a little early to let you know what it's all about. Running the new iOS4 operating system, the iPhone 4 features a completely new, edgy design with a faster processor, a front-facing camera, and more.

Design

The design of the iPhone 4 really sets it aside from its predecessor, the iPhone 3GS. This is the first time Apple has really changed the design of the iPhone since the release of the first 2G version a few years ago.

Click to enlarge (image courtesy of Apple.com)

The iPhone 4 has a thinner design that the 3GS and 3G versions, and it really feels thinner to the touch too. It's 24% thinner than the 3GS and measures only 9.3mm thin. It weighs 4.8 ounces, which is a negligible 0.1 ounces heavier than the 3GS. The stainless steel design along the edges looks beautiful and didn't show any fingerprints, but the glass front and back panels showed almost every fingerprint possible. (The White iPhone 4, however, doesn't show any fingerprints due to the color). The new stainless steel edge design doubles as the antenna, which Apple says will boost the signal strength, but that will be decided with some long-term use.

Click to enlarge
(image courtesy of Apple.com)

Along the side, there's still the usual volume controls and silence switch, but now the volume rocker of the previous models is gone and replaced with two separate + and - buttons made of the same stainless steel.

The SIM slot at the top of the 3GS is gone and has been moved to the side of the iPhone 4. Also different in this department is the use of a micro SIM instead of the traditional full-sized SIM card found it almost all mobile GSM devices today. This less-used micro SIM means it will be harder to change networks after your contract runs out or harder to buy an iPhone 4 without a contract and just insert your current phone's SIM card. In time, however, you may be able to go to AT&T and ask for a micro SIM for a small fee.

On the backside, there's a beefed up digital camera (5 megapixels) and has a LED flash that can be turned on and off.

Click to enlarge (image courtesy of Apple.com)

Retina Display

The iPhone 4 has a Retina Display, which features a 960 x 640 resolution in the same 3.5-inches, which amounts of around 330 pixels per inch. This new model has four pixels in the same space that had only one pixel in the iPhone 3GS. With past models, if you looked closely, you could somewhat easily make out each individual pixel, but the Retina Display packs the pixels in so tight that the human eye cannot see the pixels individually. Because of this, the new screen looks absolutely beautiful and is without a doubt, the best screen on a smart phone. The new display also has an 800:1 contrast ratio, which is four times better than the 3GS.

We would have liked to see an OLED screen, however, but the improved IPS technology that Apple has used allows for an extremely wide viewing angle.

Internals

The iPhone 4 has the all new Apple A4 chip, which is the same as the iPad's and is designed by Apple themselves. Performance with the iPhone 4, Apple says, is quicker than the iPhone 3GS, which also touted improved speed, but is relatively identical to the 3GS.

Because of the A4's slim design, this allowed their engineers to free up space inside of the iPhone 4's body, which was then used for a larger battery. Apple says the new model can go for 7 hours of talk time, 6 hours of 3G Web browsing (10 over Wi-Fi), 40 hours of music playback, or 300 hours of standby non-use. These numbers are all better than the 3GS's, but again, they're all ratings by Apple and not real-world tests, but there's no doubt an increase.

Apple made available two memory options, 16GB and 32GB. We were surprised a 64GB model wasn't made available, especially with HD video recording now supported.

Another motion sensor is now built-into the iPhone 4: a three-axis gyroscope. This senses the phone's yaw, roll, and pitch. The other standard proximity and ambient light sensors, accelerometer, and compass are also included.

Click to enlarge
(image courtesy of Apple.com)

As mentioned earlier, the camera on the back as been bumped up to 5 megapixels and now has a fairly bright LED flash, which should help take pictures in darker settings as this is something the iPhone has been weak in. The backside camera can also record video in high-definition now with a resolution of 720p at 30 frames per second.

The new frontside camera is VGA and has a resolution of 640 x 480. Apple claims this front camera has been designed and tuned for use with FaceTime, especially for taking pictures and video in a self-portrait style at a distance of an arm's length.

FaceTime

FaceTime is Apple's video calling feature that currently only works over Wi-Fi, but will support cellular networks in the future. In order to use the front-facing camera for a FaceTime chat, the other caller must also have an iPhone 4. There's no setup required and works right out of the start. The mediocre quality of the VGA camera is apparent and some slight lag is also present. FaceTime can also utilize the backside 5 megapixel camera too.

iMovie

The iMovie application for the iPhone 4 available from the Apple App Store lets users edit and jazz up photos and videos shot with the camera. There are themes, transitions, and some other effects that can be utilized to make content look a little more "special". The application costs $4.99 from the App Store through iTunes.

(image courtesy of Apple.com)

iOS4

iOS4, the newest version of Apple's mobile operating system, is already available for download for users of previous iPhones and iPod Touch models. For more information about iOS4, including a full review, screenshots, and all the details, read our review and walkthrough of iOS4.

Pricing

The Apple iPhone 4 is priced at $299 for the 32GB model and $199 for the 16GB model. These prices are for new AT&T customers signing up for a 2-year contract or current AT&T customers eligible for an upgrade with a 2-year contract renewal.