Picking a new iPhone: there's only one decision that matters

It's simpler than you think


Starting at 12:01AM PT (3:01AM ET), you'll be able to preorder the just-announced iPhone 6 and iPhone 6 Plus from Apple. If history serves any indication, hundreds of thousands, if not millions, of people will place their preorders this weekend, consuming all of Apple's stock and pushing availability of the devices out for weeks or months.

That's been the same story every year for half a decade, but this time around, Apple is selling two distinctly different iPhones with different sets of features, different price points, and seemingly different cameras. That makes it a little harder to wake up in the wee hours of the morning and just click the buy button like you could in prior years. Based on talking to people in person and on social media networks, it seems that a lot of people are torn between the iPhone 6 and the iPhone 6 Plus and are completely unsure of which one to buy. It appears that for most people, the biggest sticking point is that the 6 Plus could take better photos than its smaller sibling, thanks to its new optical image stabilization system. But the answer is simpler than many people are making it out to be.

The differences between the two devices have been agonized over ad nauseam for the past couple of days, but here are the highlights: the iPhone 6 has a 4.7-inch, 1334 x 750 pixel display, while the iPhone 6 Plus has a 5.5-inch, 1920 x 1080 pixel display. The iPhone 6 Plus comes with optical image stabilization (OIS) on its 8-megapixel camera, while the smaller iPhone 6 does not have that feature. And the iPhone 6 Plus has a bigger battery. Apple has also tweaked iOS 8 for the 6 Plus' larger screen with a new landscape homescreen mode.

Both screens are considered Retina HD by Apple, and though the 6 Plus has a higher resolution, both are pixel dense enough to make it difficult to see individual pixels with the naked eye. Unsurprisingly, the 6 Plus is much larger than the 6, measuring 3.06 inches wide by 6.22 inches tall verses 2.64 inches wide by 5.44 inches tall. (If you've ever held one of Samsung's Galaxy Note 3s, the 6 Plus has nearly the exact same dimensions as that.)

According to Apple, the 6 Plus' larger battery will last for 12 hours browsing the web over LTE or up to 16 days of standby. The iPhone 6 is rated for 10 hours of LTE web browsing or 10 days of standby.

Until we have been able to put the iPhone 6 and iPhone 6 Plus through our review process, we won't know for sure how much of a difference the 6 Plus' longer battery life makes in the real world (though Apple's suggested guidelines have been reliable in the past). But it's safe to say that the iPhone 6 Plus will last longer between charges than the iPhone 6, and if battery is your number one concern, that might push the 6 Plus ahead regardless of the other differences. For the rest of us, that leaves the actual size of the devices and the OIS feature as the remaining factors.

To understand how important (or not) OIS is in a phone, it's important to understand how it actually works and what it actually does. OIS has been around in DSLR lenses and point-and-shoot cameras for over a decade, and other smartphone manufacturers have been putting it in their devices for years before Apple jumped on board. It is designed to counteract hand-shake and camera movement, by literally moving elements of the camera's lens in the opposite directions of the photographer's movements. This allows for taking sharp pictures with longer shutter speeds than would otherwise be possible. Longer shutter speeds let more light into the camera's sensor, allowing for brighter pictures in low light environments. It's long been billed as the savior for low light photography and it lets you use a really big zoom lens on your DSLR or mirrorless camera without a tripod. OIS is most effective when you have a long focal length, because that magnifies any uncontrollable movements you might have.

OIS only corrects for camera shake, it does not make your subject sit still

But, and here's the key misunderstanding with OIS, it is only able to correct for movement on the camera's side. If you have a longer shutter speed, unless your subject is inanimate and perfectly still, it's more likely that your subject will move in the time that the camera is taking the picture, causing motion blur that the OIS system can do nothing to correct for. You've seen this before, often times when you try to take a picture of a frisky pet or active toddler indoors, they move during the shot, causing a blurry limb or loss of sharpness in key areas such as the face. Having OIS in a camera does not resolve this problem, and in fact, a lot of smartphone manufacturers have exacerbated the issue by relying too heavily on the feature and holding the shutter open for longer than would otherwise be necessary. (I've personally seen this with every smartphone I've reviewed that has OIS, including models from HTC, LG, and Nokia.) And since smartphones have wide lenses, OIS is less effective than it would be on your DSLR with a 300mm zoom lens.

The fact is, most of the pictures people take with smartphones are of other people, which are living, breathing, and yes, moving subjects. The most important factor in getting sharp pictures of people is shutter speed — it needs to be fast enough to freeze the subject.

That isn't to say the OIS feature has no purpose — it's really great for getting sharp pictures of buildings at night or those cool nighttime cityscapes. They aren't moving and will surely sit still long enough for the camera to use a longer shutter speed. OIS can also be effective for stabilizing video. It can also be argued that OIS is more effective in the iPhone 6 Plus (and possibly more necessary) than it would be in the iPhone 6 because its larger size can be more difficult to hold steady.

In Apple's description of the OIS system on the iPhone 6 Plus, it says that it is capable of fusing both long and short exposures in the same shot in an effort "to reduce subject motion." Earlier iPhones, like the 5S (and also the iPhone 6), combined four short exposures to fight handshake and subject motion. The extra step the iPhone 6 Plus does is add the long exposure, but we won't know exactly how much of a difference that makes in real-world practice until we're able to put the phones through our review process. It's possible that the iPhone 6 Plus' system of fusing exposures could alleviate the issues we've seen with OIS in other smartphones that do not do the same kind of processing.

By all accounts, it appears that everything else about the cameras in the iPhone 6 and 6 Plus are the same. According to Apple, they have the same resolution, same sensors, same focus system, same lens, same flash, and same new camera processing features. They also have the same video recording features, including slow-motion, 1080p recording, and something Apple calls "Cinematic Stabilization." But in the vast majority of still photography situations, these cameras are likely to produce very similar results.

iPhone 6 colors

So the real question you need to answer before clicking that buy button is "Do I want a really big phone or not?" The iPhone 6 Plus is a really big phone. It's going to be awesome for watching video, browsing pictures, reading books and comics, browsing the web, and all of the other things that people have been doing on really big phones for years. It will likely take the place of a small tablet for many people. But it doesn't do that without compromises. Just like any other big phone, the iPhone 6 Plus is going to be difficult to use in one hand (even with Apple's software tweaks) and it's not going to slide into your pocket nearly as easily as a smaller phone. Though the iPhone 6 has a considerably larger display than the 5S before it, we've seen that 4.7-inch phones can certainly be used in one hand and they fit in any pocket you wish to put them in. A simple test to see if this works for you is to print out pieces of paper in the dimensions of the iPhone 6 and 6 Plus and try them out in your hands and in your pockets. Here are handy templates for the iPhone 6 Plus and iPhone 6 (make sure you set your printer to A4 before printing).

Do you want a really big phone and are you willing to live with the compromises that come with it? Great, you should get the iPhone 6 Plus. If you want a phone that will be easier to manage in one hand and will fit in your pants' pockets with ease, the iPhone 6 offers virtually everything the 6 Plus has in a smaller package.

It's as simple as that. Now comes the really hard question: what color do you want?

Update 9/12/2014, 3:30PM ET: This article has been amended to include a description of how the OIS system works in the iPhone 6 Plus, according to Apple.