The Apple iPhone 4 is the thinnest smartphone in the world with the highest resolution display ever built into a phone handset. Read our full Apple iPhone 4 review to find out if it should be your next mobile phone. Updated July 29 2010.

Also see iPhone 4S review

The Apple iPhone 4, as the name suggests, is the fourth generation of Apple’s game-changing smartphone. It’s already garnered far more publicity than the previous three models – if not entirely for the right reasons.

Few could have escaped mass-media news coverage of reception issues highlighted by Apple’s unusual choice of design, which sees the iPhone 4’s aerials fixed around the outside of the handset. But before we examine the minutiae of antennae, let’s look at the technology changes found in the iPhone 4, and how it compares to its own predecessors.

Apple makes a big play about the slimmed down casework. If you lay an iPhone 3G down next to the 4, you can plainly see the latter is thinner, matching the 25%-thinner boast. Yet in the hand, the iPhone 4 actually feels chunkier.

That’s entirely due to differences in the way the case is shaped between models – iPhone 3G and iPhone 3GS had a curvy form with rounded back and soft-radiused edges. But the iPhone 4 is a dense slab with square edges, seemingly heavier, although at 137g it’s only 4g more than an iPhone 3G, and 2g heavier than the iPhone 3GS.

Net result – it feels thicker in the hand. But it’s beautifully weighted and feels solid, against the 3G’s thinner-feeling form with its plastic back.

Front and back are now formed from toughened glass, and while we’ve not managed to scratch either side yet, we prefer to carry the 4 in a case that covers the back – the face that comes into most contact with the real world when lying down.

Retina

A simple comparison of screens between this phone and the 3G/3GS shows that there is in fact no comparison – the Apple iPhone 4’s display is richer, more colourful and much, much sharper. With four times the pixel resolution, that’s hardly surprising. You can now read – subject to eyestrain – every word on a webpage built for desktop PC dimensions, even fully zoomed out.

We noticed that small text on a webpage looked less bold, like a ‘light’ version of the font had been substituted. But compring back to an iPhone 3G screen showed that the older screens used plenty of anti-aliasing to reduce jagginess but make the type fuzzier. The iPhone 4’s typography is so clean, it looks almost lightweight.

All the extra graphics processing of four times the pixels has not slowed down the rendering of images one bit. In comparison to our 3G especially, the iPhone simply flies in its interface responsiveness. Pinch to zoom actions carry no lag, leaving pages and photos to scale up and down as quick as your fingers can dance over the silky screen.

Camera Time

Other headline features added to the iPhone 4 include two new cameras – facing fore and aft – which enable internet video calling and high-definition video shooting respectively. At present the only way we’ve found to use the video webchats is with Apple’s own implementation of video-over-IP, FaceTime. This works very well when it works – which is to say almost every time we tried.

With its vivid, sharp and essentially glitch-free video to enjoy, we can guess why Apple made the facility Wi-Fi-connections only. Even seven years after 3G-video calling was first promoted for mobile phones, the breadth of coverage and consistency of 3G connections is still too patchy to make reliable video chatting viable. Most phone networks’ strained infrastructure would probably fail further when hit by widespread videocalling.

Apple certainly didn’t invent phone video chatting, but it did turn it into something that’s a joy to use. Using Facetime really is a doddle. Make a regular voice call over GSM, and if both parties are on a WiFi connection you just press the FaceTime on-screen button.

Your voice call is terminated (so you don’t use paid-for talk-time) and you’re transferred to a purely data connection. You’ll see the image of your chatting partner onscreen, with your own face in a small, draggable thumbnail. Tip the phone sideways and images automatically adjust to fit landscape mode. And rather than keep the focus on yourself, you can tap an on-screen icon to switch to rear camera, showing your friend your point of view.

We found that rear-facing camera to give admirable results when used for snapping hi-res stills, or taking HD video. Still images are bright and finely detailed at their new-found 5Mp (2592 x 1936 pixel) resolution. Zoom in to actual size and you’ll see a little JPEG noise – but this kind of microscopic nit-picking is normally reserved for a review of a dedicated camera. A white LED flash helps indoor shots, with simple on/off/auto switching overlayed on the full-screen viewfinder. You can even switch to the video VGA camera here for easy group self-portraits.

But video recording is even better. We tried the video camera on the Thames boat-trip with some moving-water shoots, tortuous scenery to capture accurately, and the MPEG-4 compression engine took the challenge by recording sharp high-definition film with no motion artefacts whatsoever.

Juggling

Multi-tasking was introduced with the iOS 4 update, and while we never missed its absence before, we now appreciate the real benefit of having apps running in the background.

More than just allowing social butterflies to have their Twitter app open all day, it means when you leave one app to start another, the switchover time is incredible quick, since the app is usually still loaded in the background, rather than having to be relauched.

This also means you’ll return to the last state that app was in – tapping Settings could take you to the menu a few pages down where you were last tweaking your keyboard layout, for instance.

The iPhone 4 has a large amount of memory by phone standards - 512MB of embedded RAM - which allows many apps to be all open at once. By double-tapping the Home button, you can see a Dock-like line of running apps, and force-quit them if desired.To do this, just press and hold an icon until a No Entry flag appears in its corner, then tap it again.

We found that in daily use, dozens of applications would still be loaded into memory - more than 40 is not unusual. The iOS 4 memory management allows unused apps to gracefully quit when the phone does need more physical RAM.

Antennae

In contrast to hiding a radio aerial inside the case of a mobile phone, keeping it outside should be a Good Idea.

But an uninsulated aerial that’s in inconsistent electrical contact with a large semi-conductive object – the human body – may be less reliable. There's been plenty of talk already of the consequences of detuning aerials, especially when fingers bridge the gap between the Wi-Fi/Bluetooth/GPS antenna (left side) and the GSM/3G antenna (right and bottom edges).

It must be said that despite using it without a case for a week, we experienced few dropped calls or problems with reception on the iPhone 4, using it on the O2 network. And subsequently, no issues at all once we’d swapped out that SIM for a Vodafone card.

What we did notice was that compared to iPhone 3G and other recent phones, the iPhone 4 had the best mobile reception we’ve experienced. It could really hang on to a data connection, for instance, deep into a train tunnel where other phones would be announcing No Signal.

On top of new functions and slick running of existing capabilities, probably the single biggest benefit has received less attention – battery life.

Many smartphones struggle to get through one day when used actively, yet our sample was still running into its third day of use. That's with 3G and Wi-Fi switched on, and taking photos and intermittent internet surfing.

Battery capacity has increased, but only by around a third. Yet somehow, despite a more powerful processor, plus a multi-tasking OS, more powerful cameras and extra sensors, the new handset’s features have been truly tempered by longer battery life.

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The Apple iPhone 4 is everything that a new piece of technology should be. It's innovative, attractive, and ahead of its competition. In comparison, previous iPhone upgrades seem inconsequential - that's how much iPhone 4 brings to the table.

The Apple iPhone 4 is available on multiple carriers in the UK. Here are details of UK pricing of the Apple iPhone, and click here for Apple iPhone 4 deals.

Apple iPhone 4: Premium Look

We spent some hands-on time with the new handset at the Apple Worldwide Developers Conference (WWDC). We'll start with the visuals: It's stylish. Whereas the iApple iPhone 3GS looks and feels plasticky, the Apple iPhone 4 is svelte and has a premium feel. Surprisingly, it achieves that impression while retaining the same general design, although the edges appear a bit more squared than before.

The Apple iPhone 4 is noticeably slimmer than the iPhone 3GS, measuring 9.3mm deep versus the iPhone 3GS's thickness of 12.3mm (that translates to around 24 percent less). The iPhone 4 is also slightly narrower, 59mm to 62mm. The weight stays the same at 136g, but the tweaks to the dimensions make the current iPhone 3GS seem downright kludgy in comparison. (See all iPhone 4 specs.)

However, it's the aesthetic design touches that make the Apple iPhone 4 stand out. The overall design screams elegance - from the rounded, individual volume up and down buttons that replace the plastic volume rocker on the iPhone 3GS to the ring/silent switch and the power/sleep button up top. The face and back are made of glass that is specially treated to withstand scratches and oily fingers, according to Apple. The side edging is aluminum, and doubles as the device's three cellular and wireless antennae.

Apple claims the glass is 30 times stronger than plastic and rivals sapphire crystals for strength. One side effect of making both the face and the back of the phone glass is that, at last, the differences between the white and black iPhone models now really mean something. In the iPhone 3G and 3GS, white and black models looked pretty much the same when viewed from the front. That’s not true anymore: if you’re using a white iPhone, you’ll know it—it’s white front and back. With the product’s straight edges, stainless steel sides, and round, dimpled home button, the white model especially hearkens back to the original iPod.

The buttons are nice, in that they require firm pressure to activate and they give a pleasant response under your fingers; it feels less likely that you’ll hit one by accident or that the volume will get changed when you slide your phone in a bag. They also have subtle + and - symbols engraved in them, letting you identify them by feel. The mute switch has also been changed; no longer the angled switch of previous iPhones, it just slides up or down; when it’s on mute, there’s a thin orange line to let you know that it’s on silent mode. Like the volume buttons, the new switch seems less likely to get triggered by accident, a problem we’ve even had when just slipping a iPhone 3GS into a pocket.

Apple has also moved the SIM card to the right side of the phone, and changed it from the full-size card found in previous models to the micro-SIM used in the iPad. According to Jobs, this was done largely out of space concerns.

Besides the usual Sleep/Wake button and headphone jack on the top of the phone, Apple’s also added a second microphone for noise canceling.

Apple iPhone 4

See all pictures of the iPhone 4

Apple iPhone 4: Sharp Display

Of course, the Apple iPhone 4 isn't just about cosmetic enhancements, pleasing as they are. What makes this phone such a technological improvement is what's inside the handset.

Like its predecessor, the Apple iPhone 4 has a 3.5-inch display. But the new phone's display doubles the resolution to a 960-by-640-pixel IPS display. At 326 pixels per inch, this is the highest resolution available on a phone to date.

That display truly makes a difference. Whereas the iPhone 3GS's text - in the menus, in apps, or on web pages - appears thick, fuzzy, and undefined, the Apple iPhone 4's text is razor sharp, even when enlarged (as we tried doing when viewing a PDF).

The new "Retina display" - so named because it surpasses the number of pixels the human retina can process - also greatly improves the sharpness, clarity, and visible detail of images.

In both cases, we'd liken the magnitude of difference to that between a standard-definition 80p DVD and a high-definition 1080p Blu-ray Disc: When you view both on an HDTV, the differences are striking. And once you see them, you can't go back.

The real value of the new display will become evident for people who spend time reading on the Apple iPhone 4. We expect the display will make reading a more pleasurable experience (although, clearly, limits will remain given the inherently modest screen size - modest, at least, as compared with handsets such as the Sprint Evo 4G, which has a 4.3-inch screen, and the much larger 9.7-inch Apple iPad screen).

The screen uses the same in-plane switching (IPS) techniques used on the displays in all the iMacs and in the iPad. As a result, the display is bright and colorful, with a massive viewing angle that really does look great, no matter which way you hold it.

Apple iPhone 4: iBooks Goes Mobile

The high-res display, coupled with the addition of iBooks on the iPhone 4 (and with iOS 4 upgrades), makes the iPhone a more relevant e-reader. iBooks retains its structure, appearance, and function from what we've already seen on the Apple iPad; and with this OS's ability to sync the iPad, desktop, and iPhone, readers gain the flexibility to move seamlessly among devices. This capability is available for Amazon's and Barnes and Noble's respective e-book readers, as well, but not for other competitors.

iBooks also gains a few new features previously unavailable on the iPad. You can now create notes and bookmarks, and see those notes, bookmarks, and highlights in the table of contents. We suspect that the notes remain trapped in line - for example, there's no way to create cheat sheets, summaries, or other such personalized shortcuts that you could then utilize on your computer or elsewhere - but these new functions are a step in the right direction.

The major new feature in iBooks is its native support for PDFs. You'll find tabs for both books and PDFs. Each one gets a bookshelf or list view (your choice). You can add PDFs via email or Safari, and PDFs can sync back to iTunes and to other Apple devices such as the iPad or Apple iPod touch.

NEXT PAGE > The iPhone 4 comparitive performance tests >>

Jump to the PC Advisor verdict >>

Video: See the iPhone 4 in action

Apple iPhone 4: the official pictures

See also: Group test: what's the best smartphone?

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The Apple iPhone 4 is the thinnest smartphone in the world with the highest resolution display ever built into a phone handset. Read our Apple iPhone 4 review to find out why it should be your next mobile phone.

Apple iPhone 4: A Computer in Miniature

The Apple iPhone 4 uses Apple's A4 CPU, the same processor powering the Apple iPad. And it runs the newly renamed iOS 4 operating system (which the iPad will also use, starting in the Autumn).

As part of iOS 4, the Apple iPhone 4 gains a bevy of capabilities. One of them - multitasking - feels long overdue, but as with Apple's long-awaited cut-and-paste feature, the company delivers on the promise of making multitasking work smoothly.

Quickly double-tap on the home button to pull up a pane that shows which apps are open. From there, you can swipe horizontally through the apps that the Apple iPhone 4 has retained in either a running or suspended state.

When you find the app you want, you just click on the icon. The app will then resume its activity, and, if written to take advantage of this new feature, it will pick up precisely where you left off. At the very least, reaccessing the app will be faster.Apple iPhone 4: Comparative Use Tests

Let's take the example of the side-by-side tests we did with an iPhone 3GS (running iPhone OS 3.1) and the Apple iPhone 4. We navigated between the Apple Safari web browser and the Photos application and back again to Safari, and then back again to Photos.

iPhone 4: On the Apple iPhone 4 using iOS 4, the phone jumped quickly and smoothly between the apps, with virtually no pause or hesitation. We left a fully drawn Web page in Safari to go to Photos, navigated to a folder within Photos, and then to a picture in the middle of that folder. When we popped back to Safari, we resumed at the fully drawn web page, and when we jumped back to Photos, we were looking at the same photo we'd left moments earlier.

iPhone 3GS: That same exercise on the iPhone 3GS required the web page to draw the first time. To change apps, we had to press the home button to exit Safari. We then went into the Photos app and found our image in its album. To go back to Safari, we pushed the home button to return to the home screen and then clicked on Safari. (On one pass, the page loaded immediately; on another, it did not). We then pressed the home button to return to the home screen, selected Photos again - and found myself back at the top-level list of Photo Albums, as opposed to drilling down to a specific image within a specific folder.

To close an app out of the multitasking bar, you click on the icon and hold. The icons then get a red button with a dash; touch there, and you can close the app.

Equally as elegant as multitasking is Apple's implementation of Folders, an increasingly necessary addition. To add icons into a folder, you simply drag one icon on top of the other to create the folder; the folder automatically gets the name of the category those apps share. Or, if you prefer, you can rename the folder on the spot. You can pack a maximum of 12 apps within a single folder (that gives you three rows of four apps across the home screen). And, thanks to the addition of Folders, you can now add up to a maximum of 2160 apps.

Apple iPhone 4

See all pictures of the iPhone 4

Apple iPhone 4: Dramatic Camera Boost

The iPhone 4 brings much-desired camera and video recording advances, as well. The primary camera on the back bumps up from 3 megapixels to 5 megapixels, while retaining the same pixel size (which can further improve image quality). The camera also gains an LED flash, a backlit sensor, and an integrated 5X zoom. The camera now lets you shoot in high-def, at 720p, 30 frames per second; in addition, video gains the tap-to-focus feature already available on the camera.

The examples that Apple showcased during its keynote were compelling evidence that these upgrades are indeed worthy ones. There's also a front-facing camera integral to Apple's FaceTime videophone app, which works only for communicating between two iPhone 4 handsets.

We got to spend some time playing with the iPhone 4’s two cameras. The rear camera is a 5-megapixel model, up from 3 megapixels on the iPhone 3GS. But megapixels aren’t everything—in fact, the iPhone 3GS camera creates better output than many smartphone cameras with more megapixels. This new camera appears to follow in its predecessor’s footsteps, though we were only able to shoot in a controlled environment in Apple’s demo area. The photos we took looked great in preview mode on the phone; we look forward to doing a more thorough analysis when we get our own iPhone 4 and use it to shoot in more varied environments.

Also new to the rear-facing camera is an LED flash. When you turn the flash on and press the shutter button, the LED flashes once to allow the camera to meter the brightness, and then a second time to take the picture. The results seemed decent, though we’ve learned from other smartphones that an LED flash isn’t always the best choice if there’s enough light to shoot without. Still, for most people the LED flash means that you’ll always be able to take a picture, even if it’s getting pretty dark. (You can set the flash to never fire, always fire, or fire automatically when the camera senses that you need it.)

The iPhone 4’s front-facing camera isn’t a 5-megapixel wonder; it’s a 640-by-480-pixel camera (three-tenths of a megapixel, if you’re curious) designed to be used primarily with the new FaceTime video-chat system, though it will also work well as a way to take self-portraits. You can flip between the front and rear camera from within the Camera app, as well as when you’re using FaceTime.

FaceTime itself worked great in the demos we saw carried out by Apple’s employees. Video quality in the FaceTime chats seemed somewhat variable; it’s definitely not a high-def video experience, but it doesn’t really need to be. (But as we learned from iChat AV, the real test with video chatting is when you try to start a chat from various and obscure network conditions.) Starting a chat couldn’t be easier, however. You dial a friend with an iPhone 4, and then tap the FaceTime icon in the Phone app to initiate a video call. There’s no app to launch and no buddy list to configure. It’s a very cool idea, though it does make us wonder what will happen when other devices—those without phone numbers, for example—join the FaceTime party.

Once you’re in a FaceTime conversation, you can readily switch between landscape and portrait orientations, or jump back and forth between the iPhone 4’s front- and rear-facing cameras—in case you want to show your conversation partner what you’re looking at. As in iChat on the Mac, there’s a small window that shows what your camera is seeing, and you can drag that pane into any of the screen’s corners.

From our early look at the Apple iPhone 4, this handset appears to be a must-have for anyone with an original iPhone or iPhone 3G (the former won't get the iOS 4 upgrade at all, while the 3G won't support some features). And people who have an iPhone 3GS will find this a worthy upgrade, too. Unlike the previous jump, from the iPhone 3G to the 3GS - which focused on slight performance improvements - the Apple iPhone 4 bolsters the hardware's digital imaging capabilities and its display, making it a comprehensive and measurable upgrade over its predecessor.

Melissa J Perenson

PC World US

NEXT PAGE > PC Advisor's verdict >>

Video: See the iPhone 4 in action

Apple iPhone 4: the official pictures

Apple iPhone 4: Specs

  • Touchscreen smartphone
  • UMTS, HSDPA, HSUPA, GSM, EDGE
  • quad-band 850/900/1800/1900MHz
  • 3.5in (960 x 640) 3:2 capacitive IPS touchscreen, aluminosilicate glass, with oleophobic coating
  • 326 dpi, 800:1 contrast ratio, 500cd/m2 brightness
  • 16GB and 32GB flash storage
  • Apple A4 (ARM Cortex A8 CPU/PowerVR SGX 535 GPU) processor
  • 512MB RAM
  • 802.11b/g/n
  • Bluetooth 2.1 + EDR
  • rear-facing 5Mp still/1280 x 720 video camera
  • front-facing 640 x 480 video camera
  • white LED flash
  • assisted GPS
  • three-axis gyroscope
  • proximity sensor
  • ambient light sensor
  • digital compass
  • dual mics
  • speaker
  • 3.5mm stereo headphone/mic jack
  • earphones with remote and mic
  • USB power adaptor
  • 5.25Wh lithium-ion battery
  • 115 x 59 x 9mm
  • 137g
  • Touchscreen smartphone
  • UMTS, HSDPA, HSUPA, GSM, EDGE
  • quad-band 850/900/1800/1900MHz
  • 3.5in (960 x 640) 3:2 capacitive IPS touchscreen, aluminosilicate glass, with oleophobic coating
  • 326 dpi, 800:1 contrast ratio, 500cd/m2 brightness
  • 16GB and 32GB flash storage
  • Apple A4 (ARM Cortex A8 CPU/PowerVR SGX 535 GPU) processor
  • 512MB RAM
  • 802.11b/g/n
  • Bluetooth 2.1 + EDR
  • rear-facing 5Mp still/1280 x 720 video camera
  • front-facing 640 x 480 video camera
  • white LED flash
  • assisted GPS
  • three-axis gyroscope
  • proximity sensor
  • ambient light sensor
  • digital compass
  • dual mics
  • speaker
  • 3.5mm stereo headphone/mic jack
  • earphones with remote and mic
  • USB power adaptor
  • 5.25Wh lithium-ion battery
  • 115 x 59 x 9mm
  • 137g

OUR VERDICT

Apple's fourth-generation smartphone really is its best yet, notwithstanding controversy about external antennae. In our tests, reception was outstanding. Its screen is the highest resolution of just about any screened gadget, with amazing colour and definition. An HD video/5Mp stills camera is joined by front-facing camera for Facetime video chats. Longer battery life (up to three days in real-life use), faster processor, multi-tasking OS and an incredibly responsive multitouch display are adjuncts to what is still the easiest and most intuitive phone ever made. An unrivalled smartphone against any other.

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