I bought a HDMI->USB video capture card, and tried to use it with my DSLR camera. It works fine in Teams, but not in Zoom. And that's because Teams selects a reasonable capture resolution that matches the 16:9 aspect ratio image produced by my camera's HDMI output at 1080p. Zoom selects the lowest possible resolution, which is 640x480, which makes me look squished. There is no setting in the Zoom interface that lets me change this.