When Apple (NASDAQ:AAPL) introduced the iPhone 6 Plus, it said the device was superior to the standard iPhone 6 in a few key ways. First, it featured optical image stabilization, while the iPhone 6 only supported digital image stabilization. Next, the iPhone 6 Plus featured a 1920-by-1080 display, offering 401 pixels per inch, while the iPhone 6 came with "only" a 1334-by-750 display, with a pixel density of "just" 326 pixels per inch.
To support the additional power draw of the larger, higher pixel-density display, the iPhone 6 Plus features a 2915 mAh battery, which offers far more capacity than the 1810 mAh battery in the regular iPhone 6.
These three features allow Apple to charge an additional $100 for iPhone 6 Plus models over the iPhone 6. Given the seemingly solid demand for the iPhone 6 Plus, and given that a mix shift toward the "Plus" models helps Apple's average selling prices and profits, I think the company will do even more with this line of phones.
Apple needed to establish the demand profile for these phones
I believe hardware specifications for the iPhone 6 and iPhone 6 Plus are substantially similar because Apple probably wanted to get a sense for the relative demand for each device.
By having the two smartphones share most components, Apple minimized the supply chain risk it faced in potentially miscalculating the relative demand levels between the models. Most of the components procured for one model could be used for the other, so Apple could shift most (but not all) parts intended for the build one device to another without problem.
However, given that Apple probably now has a good sense of the relative demand or the 6 and the 6 Plus, it can more comfortably use different and improved components in the next "Plus" iteration without the uncertainty that likely loomed ahead of the 6 and 6 Plus launches.
What I expect
I expect the next-generation "Plus" iPhone will feature the following improvements over the smaller one:
- Faster applications processor. A larger, thicker chassis likely supports greater heat output. This leads me to believe Apple could include a higher-performing chip that consumes more power in the next iPhone. Given the higher screen resolution of the "Plus" model, I'd expect a faster graphics processor than what is found in the "standard" iPhone (although I had expected that with the iPhone 6 Plus and it didn't materialize).
- More memory. Given that the larger iPhone is likely to be more conducive to multitasking than the smaller model, it would make sense to include more memory in the Plus variant relative. I wouldn't be surprised to see Apple stick with 1 gigabyte of memory for the standard iPhone 6s and then include 2 gigabytes in the 6s Plus.
- Better camera. I'd expect the next-generation standard iPhone will feature optical image stabilization (currently found in the iPhone 6 Plus but not in the iPhone 6), meaning Apple would need a new "exclusive" feature for the 6s Plus. An obvious option would be a higher-resolution sensor for the 6s Plus.
I'm not sure if Apple will upgrade the displays on the next round of iPhones. While the competition will be moving to even higher resolution and pixels-per-inch displays, the higher power consumption and increased costs might not be worth the effort for Apple, particularly since both the iPhone 6 and 6 Plus already have exceptional displays.
At any rate, I think Apple wants people to buy up, so the more interesting features and improvements it can pack into the "Plus" model while keeping the cost structure reasonable, the better. I can't wait to see what this year's iPhones, particularly the larger model, will feature.