The iPhone 6 Reviewby Joshua Ho, Brandon Chester, Chris Heinonen & Ryan Smith on September 30, 2014 8:01 AM EST
At a high level, video recording seems to be mostly similar. Both the iPhone 5s and iPhone 6 continue to rely on EIS for video stabilization, both seem to use somewhat similar optics and sensors, and both can only shoot 1080p video. However, the details are really where we see improvements in the iPhone 6. For starters, the iPhone 6 now has 1080p60 video support, which is definitely helpful for improving spatial resolution and general performance. There's also 720p240 slow motion video, which is an addition to the 720p120 video that we saw in the iPhone 5s.
|Video Encode Settings (Approx.)|
|iPhone 5s||iPhone 6|
|1080p30||17 Mbps High Profile H.264||17 Mbps High Profile H.264|
|1080p60||-||27 Mbps High Profile H.264|
|720p120||27 Mbps High Profile H.264||31 Mbps High Profile H.264|
|720p240||-||42 Mbps High Profile H.264|
As you can see, there's really not a massive difference in encoding bitrate, at least for the standard video record settings. However, even casual examination shows just how big a difference there is when comparing video from the iPhone 5s to video from the iPhone 6.
While the YouTube compression is likely to make it hard to see whether the iPhone 6 really has better video quality, when viewed at full resolution with Quicktime it seems that there is some level of improvement, but this could be due to the smaller field of view that is used when compared to the iPhone 5s. This tighter FOV also seems to be part of the reason why the stabilization is more effective than before. At various points in the video, it's quite obvious that the iPhone 6 is also benefiting greatly from PDAF as we see seamless transitions throughout the video and consistently better focus while the iPhone 5s is locked from the start and would require multiple taps to refocus the video.
1080p60 brings significant improvements to temporal quality, as capturing fast motion is noticeably more fluid when compared to 1080p30. Video stabilization is also retained, which makes 1080p60 an easy choice when capturing fast-moving objects.
As with the iPhone 5s, the original video on NAND is saved to play back at either 120 or 240 fps, but on the phone and when uploaded to social media the slow motion versions play back certain parts at 30 fps. As far as I can tell, there's relatively little difference in the image quality between the two modes, but this advantage is unlikely to hold when in lower light situations as the frame rate inherently caps the exposure time.