If you want to record the smoothest 4K video with an iPhone, skip the 6s and go with the 6s Plus.
The two new iPhones appear to be identical in almost every way except screen size, but in a new 4K video comparing the digital stabilization of the iPhone 6s against the optical/digital stabilization on the iPhone 6s Plus, the new camera on Apple’s bigger-than-big iPhone is clearly superior.
Check it out for yourself:
The folks at Giga Tech shot the comparison video above that highlights the iPhone 6s Plus’ extra stability. You can definitely notice a bit more shake on the iPhone 6s side. Of course if you’re trying to get perfectly still, pro-quality 4K video from an iPhone you’re going to need a dolly or a gimbal anyway.
While both new iPhones offer video stabilization, the iPhone 6s only has digital image stabilization which isn’t as effective when recording 4K. Giga says that the digital stabilization on the 6s does work much better when recording Full HD videos though.