Image source: Apple. 

Though the iPhone 6s and 6s Plus are barely a month old, it's always interesting to think about what Apple (NASDAQ:AAPL) might have up its sleeve with its next-generation iPhone 7/7 Plus smartphones.

There's always plenty to speculate about, particularly given how multifaceted a smartphone is, but I'd like to go over the main camera improvements that I believe Apple will bring to its next-generation iPhones.

No. 1: Optical Image Stabilization for the 7
Apple first introduced a technology known as optical image stabilization for still photos in the iPhone 6 Plus last year -- the vanilla iPhone 6 was left out of the loop. This year, it still left out optical image stabilization from the iPhone 6s, but gave the 6s Plus camera the ability to utilize optical image stabilization for videos as well.

I suspect that with the iPhone 7, Apple will make optical image stabilization -- for both still shots and for video -- standard across both models. Even mid-range Android phones are starting to include this feature, so I believe that Apple will need to include this feature in all of its phones next year simply for competitive reasons.

No. 2: Six-element lens
Ahead of the iPhone 6s/6s Plus launch, Business Insider reported speaking to a person within Apple's supply chain and learning that Apple is planning to transition to a six-element lens in a "future iPhone intended to be released after the iPhone 6s" -- in other words, the iPhone 7.

The report, which you can read here, offered a lot of insight into why a greater number of elements is better, but the bottom line is that more elements means that the camera can "absorb more light" leading to "clearer and sharper images."

No. 3: Larger rear-facing camera aperture
Recent Android flagships such as the Samsung (OTC:SSNLF) Galaxy S6 and the LG G4 have included cameras with large f/1.9 and f/1.8 camera apertures, respectively. In contrast, the iPhone 6s, like the iPhone 6 before it, features a maximum aperture of f/2.2.

Although I highly recommend reading this primer on camera aperture to better understand what it means, the bottom line is that the larger the aperture, the more light that the camera can let in, which makes for higher-quality low-light images. 

It seems like a no-brainer to expect that the camera on the next iPhone will include a larger maximum aperture than the one seen on the iPhone 6s/6s Plus.

No. 4: 4k60 video recording
With the iPhone 6s, Apple introduced support for 4K video recording at 30 frames per second. I suspect that Android flagships that will begin rolling out in the first half of 2016 will include support for 4k video recording at 60 frames per second.

Given that Apple is likely to want to maintain camera leadership against the Android flagships (particularly as it aims to maintain/grow its already large share in the premium smartphone market), I suspect that one of the enhancements that it will include in the iPhone 7 is 4k video recording at 60 frames per second.

Why are camera improvements so important to investors?
At the end of the day, it's Apple's job to make sure that customers are interested in upgrading to the latest iPhones at a rapid clip. Since the smartphone is what most people use for cameras, and given how much people seem to like taking pictures, delivering leadership cameras is an absolute must for Apple if it hopes to maintain high share in the high end of the smartphone market.