I am rendering a virtual object on a video feed, and I want to try zooming in on it. Right now, I:

rotate and translate the camera by where it actually is with respect to the object,
make a 2D texture of the latest frame filling up the entire screen, and
draw the object at the origin after multiplying the vertices by a rotation matrix.

The position is a 3D-vector, and the orientations of the object and camera are quaternions.
How can I zoom in on the object while simultaneously magnifying the texture?
If you are using perspective matrix adjust you field of view. Smaller fov bigger the object
Zooming onto an object and background in OpenGL