have problem with my footage side cam

1557104636_18507592545ccf87fc887856.78526731_Foto 22-04-19 13.53.31.jpg
1557104636_7746805565ccf87fcd96186.47121030_Foto 22-04-19 13.53.46.jpg
1557104637_17457651665ccf87fd351134.82743274_Foto 22-04-19 15.21.58.jpg


Hello guys,
I have a problem with my sidecam.
the recording is very small (can be seen in the picture)
but if i crop and zoom using the video editing application can be seen clearly.
the question is why is my own not the same as the record of host hajimoto or like having matt dubber?
can you give me advice what is wrong?
camera specifications:
cam action 4K (china product)
the lens has been replaced with a non-distortion lens
 
I know with a GoPro 4 they recommend a flat non distortion lens 4-6mm. I think the get them from https://www.peauproductions.com/ look at hajimoto videos on YouTube

yes I know what hajimoto did with the camera, he replaced it with a non-distortion lens too. but why isn't my camera like the hajimoto's camera, does the camera use digital zoom?