Picture Vignetting Yellow Corners

[58webbing]

I have just taken delivery of a Chasing Dory and have been setting it up. After finding problems linking it to 2 different DooGee phones (App stopped working message) I succeeded with a Huawei tablet and a ulePhone. Overall I think I am pleased with my purchase however am disappionted with the picture quality. The picture is not sharp at any distance and there is the annoying yellow corner vignetting as shown in the photo.
Has anyone else experienced this? Can this be fixed? Am I being too fussy? I have not seen it on other Dory media
All my searches on this subject drew a blank, this is my 1st post so if I have pressed a wrong button or resurrected an old thread forgive me.

 

[YoucanPhil]

Your camera is catching the edge of the shell.

 

[58webbing]

It seems I was worried over nothing. Although the camera was capturing the edge of the case in open air, once in water it was perfect. I would guess that an altered refraction index had something to do with it. Has anyone else noticed this? You can see the field of view alter as the drone is moved from air to water and vise versa.
The only thing I had to modify on my drone so far was a dodgy charger connection lead which would barely make contact.
Onwards and downwards.

 

[YoucanPhil]

There is a natural overscan in all videos.