Focal length of Indoor Camera?

I have a number of Ring cameras (3) and doorbells (2) around outside my house and have another one to install soon to complete coverage. Separately I was thinking of adding a wired Indoor camera to monitor my 3d printer, but it would need to focus on moving objects only about 0.3m or 1ft away. I know there are cheaper options but to have it included in the existing app would make life much simpler than using another app or browser. Can someone advise what an image looks like when this close to the camera ? '