Video Image Border or Size issue

[GRM]

I noticed that I have what is essentially a black frame around my video, so my image looks smaller than other participants in the same meetings.  I am connecting using a Nikon SLR camera and believe it is related to my camera settings.  Does anyone know how to adjust this?

[GRM]

If it triggers anyone's input, it is a Nikon D4 using a Focusrite interface for a ZOOM meeting?

[MarthaLG]

Unfortunately, I can't help, but I am having trouble with my headshot when I turn video off. My headshot is tiny with a big black border. If I figure it out, I'll add info here...