What is the difference between F2.8 4.1mm FOV 90° lens and F2.8 3.87mm 16M 90° FOV lens?

[Cindy]

What is the difference between F2.8 4.1mm FOV 90° No Fish Eye replacement lens for Git2/GoPro and F2.8 3.87mm 16M 90° FOV replacement lens for Git2/Hero4?

 

[VIOFO-Swin]

They have different "focal length", one is 4.1mm, and the other is 3.87mm.
Lens with a short focal length can provide wide angle of view, lens with a long focal length can provide small picture angle.

 

[Emily Ma]

The only difference is in focal length. F2.8 4.1mm FOV 90° No Fish Eye replacement lens have 4.1mm focal length, while F2.8 3.87mm 16M 90° FOV replacement lens has 3.87mm focal length. The former has smaller viewing angle than the latter one.

 

[Vicky Zhang]

The focal length is different. One is 4.1mm and another one is 3.87mm. With long focal length, you can see further but the angle of view close to the camera will be small. You can see the following picture for reference.

 

[May]

There is no big difference between them