As we get closer to September, iPhone leaks are pouring our more and more. The most significant leak so far has been from Apple itself when unreleased HomePod firmware was leaked and later torn apart. Another new piece of information uncovered by iHelp suggests the iPhone 8's main camera could record 4K video at 60 fps. A screenshot of the code uncovered can be seen below. The defining piece of code is: [CAMCaptureCapabilities isBack4k60VideoSupported]. There's another identical piece of code that says Front instead of Back, which suggests the front camera might even be capable of...
Source: http://www.gsmarena.com/iphone_8_might_record_4k_in_60fps-news-26575.php