GoPro 8 Digital Lenses

BACKGROUND

GoPro released GoPro Hero 8 in October 2019¹https://www.prnewswire.com/news-releases/gopro-now-shipping-hero8-black-cameras-300937053.html. The camera’s lens is now renamed as digital lenses. In previous models, the lens was named Field of View (FOV).

Digital lenses allow a user to produce a final output in either one of these four offered modes; Wide-, SuperView-, Linear– or Narrow-mode.

I have been using GoPro since 2019 and it²The different types of lenses/views only caught my attention after watching a youtube video³GoPro HERO9 Black Cinematic 5k Footage & Review, https://www.youtube.com/watch?v=BFYt6PtyDyw on February 7, 2021. The YouTuber⁴Parker Walbeck narrated that using digital lenses is in effect cropping the input to produce the final output.

SHOOTING AND PRE-PROCESSING

GoPro shots natively in the Wide-mode. Any choice for SuperView, Linear, or Narrow is digitally cropped frame after the input has been captured. Then the cropped frame is interpolated (re-scaled) to get to the desired resolution.

Take, for instance, shooting in 4K in the Linear-mode. GoPro input sensor captures in the Wide-mode in 4K. It crops the shot (can be seen as digitally zooming-in) and alters the fish-eye distortion. These procedures straighten the “object” in the input and reducing the frame dimension. In effect, at this stage, the frame is no longer in 4K resolution.

In finalizing the output, GoPro digitally enhances and interpolated the pixels by re-scaling the cropped frame to the desired 4K resolution (whether it is 4:3⁵4:3 in pixel dimension is 3840?2880 or 16:9⁶16:9 in pixel dimension is 3840?2160 aspect ratio).

STABILIZATION AND ADDITIONAL LOSS OF INFORMATION

If the Hypersmooth EIS⁷Electronic Image Stabilization, it is real-time digital image stabilization. This technique shifts the electronic image from frame to frame of video, enough to counteract the motion. is activated, then the cropped video frame will lose an additional 10% of information around the edges.

TAKE-AWAYS

1. GoPro has a static lens and shoots only in the wide-mode.
2. Wide-mode with no stabilization is the closest to native.
3. Linear-mode is a crop from the wide-mode.
4. A video shot other than in wide-mode suffers data loss.
5. A 4K video shot other than in wide-mode is not a real 4K output captured from the sensor.