Benefits of higher video resolutions
A commonly mentioned argument to dismiss recording at higher video resolutions is not currently owning a monitor or television with the according resolution (e.g. 2160p).
However, even if one does currently not own a monitor to match the resolution of the recorded video footage, recording at a higher resolution still beings the following benefits.
Even if one does not own a display that matches the resolution of a higher resolution video, one will likely own such a monitor in future.
Example: If one bought a 2160p television today, 2160p videos recorded in 2014 could be enjoyed in full magnificence today.
Some video players support zooming into the video during playback. A higher video resolution allows for further zooming and a superior level of detail.
In addition, higher resolutions allow for more leeway for cropping in a video editor.
Software that can add digital video stabilization requires cropping the image to compensate for camera movement. With higher resolution video footage, there is a greater resolution to spare after applied digital video stabilization.
Consumer video cameras use 4:2:0 chroma subsampling, which means that while all pixels of each video frame contains brightness information, only every fourth pixel contains colour information. That colour information is stretched to fill each group of 2×2 pixels.
This mechanism for saving space storage reduces space storage consumption to
Higher bit rate
Even if one does not own a 2160p monitor, video cameras (including mobile phones) select a much higher bit rate for 2160p video, which visibly reduces compression artefacts when viewed on a 1080p screen compared to 1080p video.
Mobile phone cameras usually record 1080p at 16 Mbit/s and 2160p at 48 Mbit/s.
Higher resolution video footage allows the extraction of higher resolution still frames that can act as a standalone photo.
Each frame of a 4K (2160p) video can act as a solid 8.3 Megapixel photo.
Each frame of a 6K (3240p) video has 18.6 Megapixels, and each frame of an 8K (4320p) video has whopping 33.2 Megapixels.
In comparison, each frame of WQHD (1440p) footage only has 3.7 Megapixels, FullHD (1080p) only 2.1 Megapixels and HD (720p) only 1.3 Megapixels per frame.
Valid arguments for lower resolutions
Recording at higher pixel rates (resolution × frame rate) requires more computing power and thus drains the battery faster, wearing down the battery quicker.
This especially is a problem on mobile phones with non-replaceable batteries.
Higher resolutions and/or framerates require higher bit rates to reduce visible ugly compression artefacts, thus demands more space storage.
However, during the 2010s decade, prices for space storage have decreased significantly, while storage density has skyrocketed.
Some cameras such as the Panasonic Lumix DMC-FZ1000 and DMC-GH4 disable optical image stabilization for 2160p 4K video recording, which means that the lens does not move to counteract handheld camera shakes.
The technical reason for this restriction is unknown.
With a lower selected video resolution, a video camera is usually able to reach higher recording framerates, which allows for smoother viewing and for slowing down during playback or editing while still having an acceptable frame rate to spare.
It should be noted that some video cameras, especially earlier phones (e.g. Galaxy Note 2, S4, Note 3, S5 and Note 4) store videos recorded at higher framerates without audio and with an altered framerate.
Although lower resolution videos are compatible to devices with insufficient chipset performance, higher resolution footage can always be converted to lower resolution footage at any later point.