Well... yes.. garbage in, garbage out. A 4K video properly subsampled to 1080 will lead to better quality, but not everyone is a videographer. It's no different than having RAW support in the still modes. Yes, it's a cool feature, but its also a cool feature that appeals to a very select crowd. For the general public, they probably wouldn't even know what a RAW file is, nevermind be able to do anything with it.
One last thing to keep in mind is that even though we live in an age of increased storage and large bandwidth, uncompressed video is still a bit of a rare find. And it'll be a bit resource-intensive to keep all those 4K videos around. A minute of 4K video will suck up... what.... 3G+, depending on the type that gets saved.
I'm not saying its pointless overall, far from it. Having the option there is awesome. But for a lot of people and how they will end us using their phones, it is pointless.
01-13-2016 02:12 PM