How can one calculate the camera distance from an object in 3D space (an image in this case) such that the image is at its original pixel width.

Am I right in assuming that this is possible given the aspect ratio of the camera, fov, and the original width/height of the image in pixels?

(In case it is relevant, I am using THREE.js in this particular instance).

Thanks to anyone who can help or lead me in the right direction!