Review: The iPhone 5S really is the best iPhone yet

The iPhone 5S and 5C arrived last month to a record-smashing first weekend of sales - 9 million were sold, with the iPhone 5S proving more popular than the less-expensive 5C. I was among those waiting in line for the new iPhone before dawn on Sept. 20 -- specifically the top-end 5S model. As a technology writer, getting the more expensive 5S made sense for me. But is the new iPhone 5S worth it for the less tech-centric?

Let's look at that question using logic and context: If your wireless carrier contract is up and you are looking for a new phone, then yes, the iPhone 5S is worth owning. With the addition of Apple's new fingerprint sensor called Touch ID, the phone's new 64-bit A7 processor, a refined camera system and the M7 coprocessor, the iPhone 5S's cutting-edge features match its still-sharp design.

Like last year's iPhone 5, the new 5S sports a glass front and aluminum back, weighing in at a svelte 3.95 oz. And like the iPhone 5, the 5S has a 4-in. fingerprint-resistant oleophobic-coated multitouch screen with an 1136-x-640 pixel resolution and a pixel density of 326 pixels per inch. Below the screen is the now-familiar Home Button with integrated Touch ID, on top of the phone is a lone sleep/wake button, and on the left side you can find the silent switch and the volume up and down.

In other words, aside from the three color schemes offered this year - Space Gray, Silver and Gold -- the 5S looks virtually identical to the old iPhone 5. The Space Gray is a lighter version of last year's black iPhone, the Silver version looks pretty much like the old white model - with the addition of the silver Touch ID ring - and the Gold iPhone 5S is more of a champagne color. It's actually much less gaudy than many Apple fans feared when it was unveiled, and it has proved to be a popular option. Two weeks after launch, all iPhone 5S models -- especially gold -- are still hard to come by.

The box contains a minimal set of accessories, including a set of Apple ear buds with built-in mic and controls, a USB/Lightning cable, a wall plug and very sparse documentation.

Pricing is unchanged, with the iPhone 5S starting at $199 for the 16GB model, $299 for the 32GB model and $399 for the 64GB model. (Those prices require a two-year contract with your wireless carrier.) The new price leader is the iPhone 5C, which comes in five colors and costs $99 for a 16GB model and $100 more for a 32GB version. In addition to the new plastic shell, the 5C has an upgraded battery and camera system, though the camera isn't as full-featured as the one in the 5S.

I ended up purchasing the 64GB iPhone 5S in Space Gray (the only color still available for sale at the local Apple Store on opening day).

Touch ID

The most obvious new feature of the iPhone 5S is the new Touch ID fingerprint sensor, which is ingeniously built into the Home button and allows you to easily unlock the phone using your fingertip. Far from just a superfluous addition, this new feature has already prompted me to change my security habits.

Touch ID is activated during the initial setup assistant, or by going to Settings>General>Passcode & Fingerprint. The software walks you through the setup process, which involves tapping and holding the Home button several times as the phone scans your fingerprint. (The iPhone vibrates every time your print is scanned.) An onscreen fingerprint graphic fills in as the print is read. You can authorize up to five fingers -- either yours or people you trust -- but you are required to have a passcode as a fallback. (The passcode can be a four-digit number or something more complicated if you want better security.)

When done, you have the option of using Touch ID for unlocking the Lock Screen and authorizing purchases in the iTunes and App Store.

It's important to note that your fingerprint information does not leave your phone and is never accessible to anything except the Touch ID sensor. The encrypted fingerprint data is stored, according to Apple, on a secure enclave in the custom A7 processor.

It took a little while for me to get used to Touch ID, as I've been swiping to unlock my phone for years. Now all I do is hold a thumb or finger on the Home button while Touch ID invisibly reads my fingerprint. After depressing the Home button to turn on the display, the print is recognized, the Lock Screen is automatically bypassed, and the Home screen icons swoop into view. Compared to swiping the screen to unlock and entering a passcode, Touch ID feels like telepathy.

The system works very well, and none of my friends who've tried to fool the sensor with their own fingerprints were successful. I've had an attempt or two where my finger wasn't recognized on the first pass, but when that happened I just had to reposition my finger. If for some reason the sensor misses three times in a row you can tap in your passcode to unlock the phone.

Touch ID has made me more security conscious, mostly because being secure is now super-convenient. I now have my iPhone require a fingerprint or passcode immediately upon lock, and the passcode is more than 20 digits long. I also changed my iCloud password to a 20-digit pass phrase. (If you reboot the 5S, or if you haven't used the phone in 48 hours, you have to enter password before you can use Touch ID again.)

To sum up: With Touch ID, I can unlock my phone and authorize purchases using just my fingertip, I don't have to type in a long pass phrase each time, and because I now have a longer pass phrase -- made practical because I don't have to enter it very often -- my phone is as secure as it has ever been.

The new A7 processor

If Touch ID is the most obvious change externally, the biggest change internally is the new A7 processor. It's a dual-core chip that's up to twice as fast as the A6 used in the iPhone 5, according to Apple. And it's 64-bit, which means it works very well in combination with iOS 7, which is now a 64-bit OS. (The built-in apps in iOS 7 are also 64-bit.)

When I first got my iPhone 5S, I tested Infinity Blade 3 and the Night Sky 2 app, both of which were compiled for 64-bit and loaded twice as fast. But there aren't a lot of third-party apps yet that have been reworked to take advantage of the A7 processor. As more such apps become available, iPhone 5S users should notice speed improvements.

Even without 64-bit apps, performance gains are noticeable in daily use, even in simple things like browsing the operating system. There's a fluid smoothness to the way apps launch, emails are deleted and animations are displayed that's not as obvious when using iOS 7 on older devices.

The new Camera app

The faster architecture is put to good use by the updated Camera app. The A7 chip features a signal processor, which results in performance gains that outclass the iPhone 5 (itself, no slouch). Autofocusing is faster, and the new hardware allows for burst mode, which lets the iPhone capture 10 photos per second when the shutter is depressed. The Camera app then processes each photo and suggests which photos in the burst are the best ones, although you can view all of them and decide for yourself.

The 5S also comes with better auto stabilization, taking four short-exposure shots, combining these shots to make one, good picture. My own results in low-light situations look better (less noise, better color matching) than shots taken under the same conditions with the iPhone 5.

This is impressive, considering the technical specs are similar: The iPhone 5S has an 8MP rear-facing camera, just like the iPhone 5. But the new camera system also uses an f/2.2 aperture and a revamped 8MP sensor that's 15% larger than in the previous iPhone. The result is that the camera gets a 33% increase in light sensitivity, making for better photos in less than ideal conditions.

For truly low-light situations, Apple has a new feature called True Tone flash. This combines a white LED with an amber LED, allowing the two flashes to act in concert to provide better, more accurate colors while minimizing the washed-out effect inherent to flash photography.

The iPhone 5S also allows you to shoot slow-motion video (120 frames per second at 720p resolution). Applying the slow-motion effect is easy. After you shoot the video, a timeline showing the frames appears at the top of the screen. You use grab handles to indicate where the slow-motion part of the video starts and stops.

Video shot in this mode export at normal speed when transferred to a computer using USB. But if you import the video into something like Final Cut Pro or iMovie, you can use the slow-motion features in either program to provide the effect. The extra frames needed for slow motion are still there.

It's also now possible to zoom in up to 3x while the video is being taken. It's a digital zoom, but that might be okay in a pinch.

Overall, the 5S takes better pictures than its predecessor. I was in the passenger seat of a friend's car and was able to capture a sunset just by holding down the shutter, giving me several good shots I'd have missed if I had to continuously depress the shutter. I'm a sucker for sunrise and sunset pics and the shots taken with the iPhone 5S show less noise compared to the iPhone 5; in addition, the colors are more accurate.

In situations where flash is needed, the dual-tone flash does offer better skin-tone matching, but it often causes red-eye. That's acceptable to me because it's easy to edit red-eye out with the built-in software. (You do so by tapping the Edit button in the upper right corner of the screen, then tapping the redeye reduction button. Pinch to zoom in on the face, and tap the area around the eye. The software is smart enough to figure out what you mean.)

The M7 coprocessor

Another new feature is the M7 chip, which is designed to process and record motion activity without taxing the A7. Recent iPhones have had an accelerometer, gyroscope and compass, but those models relied on the main processor, which isn't as efficient as offloading data onto a dedicated chipset. That makes the M7 great for fitness apps, as they don't have to run in the background eating away at battery life. Instead, they can just access the data collected by the M7.

The M7 isn't only for fitness apps; for instance, the built-in Maps app uses it to track whether or not you're in your car driving. If you park and hoof it, the M7 chip notes the change and Maps delivers walking directions to compensate.

Apple offers another example of the M7 in action: your phone hasn't been moved for a while, the iPhone figures you're either busy or asleep, and reduces background network activity to conserve battery life.

To test the M7 chip, I downloaded an app called Argus. After giving the app permission to use the M7, Argus began recording how many steps I had taken, starting back a few days prior to the app install. The M7 can store seven days worth of data, giving apps that take advantage of it some historical data -- even before you start using it.

When used on pre-iPhone 5S phones, Argus is capable of draining 20% to 30% of battery life per day while running in the background. With the M7, however, Argus no longer needs to be running to keep track of movement -- all of that data is tracked by the M7. As a result, Argus no longer uses up extra battery power while running in the background and the stated battery life from Apple -- 10 hours of 3G talk time, 250 hours of standby -- remains intact.

I'm eager to see how developers incorporate this into their apps moving forward.

Final thoughts

When I reviewed the very first iPhone in 2007, I called it tomorrow's technology today. Apple has spent every year since making the iPhone better, incorporating features that are actually used and not throwaway additions to a feature list.

Aesthetically, I have always loved the iPhone's design. That hasn't changed with this model, and, though I initially wanted the Silver model, the Space Gray -- with its glass front framed by the lighter gray aluminum - is the one I'll be keeping. To me, it looks like a tiny monolith from 2001: A Space Odyssey. In fact, the lighter aluminum framing the Space Gray model delivers what I think is the best of the iPhone 5 and 4S designs.

However, the main problem with the iPhone is also the reason it looks amazing: its aluminum design. Sure, it makes the phone look and feel great, with its sturdy construction and quality materials; out of the box, there isn't a more elegant looking phone. However, after some time getting knocked about in a pocket, the coated aluminum can be chipped, leaving ugly scratch marks.

As for battery life, I've found the iPhone 5S' battery life is roughly on par with the iPhone 5. Yes, the 5S has a larger capacity battery, but the phone also has new hardware that needs more juice. The result is that the 5S gains speed and processing power without losing any significant battery life.

Clearly, the iPhone 5S is an improvement over the iPhone 5 in every facet. Now that I've used an iPhone with Touch ID I can't imagine not having it. After growing accustomed to the picture quality taken by the 5S, I'd rather use its camera (with dual-tone flash and slow-motion video). After a year with the reliable iPhone 5, I prefer the iPhone 5S because the 5S improves an already great experience.

If you're due for a phone upgrade, this phone is highly recommended. But if you still have another year or so on contract, remember this: if history serves, there will be features that improve over the 5S on the iPhone 6 and then 6S and so on.

Michael deAgonia, a frequent contributor to Computerworld, is a writer, computer consultant and technology geek who has been working on computers since 1993. You can find him on Twitter (@mdeagonia).