DJI tells us that the Osmo Action has a 1/2.3″ CMOS sensor, and although GoPro is not as forthcoming with its sensor information, we know that both action cameras offer 12MP image resolution, which you can easily print to A3 size.
Each camera has a built-in wide-angle lens with a bright f/2.8 aperture perfect for taking vibrant action shots. But, where the Osmo’s field of view (FOV) is fixed at a 145º angle, the HERO offers selectable FOV options that extend from Linear to Superview Mode for that ultra-wide fish-eye effect. This means that with the HERO, you can take in more of the scene which makes more sense for an action camera. To remove barrel distortion, both cameras have you covered. With the Osmo, it’s Dewarp and with HERO it’s Linear Mode, but what makes the Osmo’s better is that unlike the HERO, you can also apply it when shooting in 4K. With each camera, the replaceable lens protectors are useful should you break them, and can take filters.
Colouration wise, the HERO has richer sky blues and foliage greens that make the scenery pop, but the Osmo captures skin tone better which is useful for vlogging. Both cameras offer flat image profiles for colour grading, and although the Osmo has HDR Mode, it does not work with Rocksteady enabled.