Camera field of view

For an ideal rectilinear projection, angular field of view along one sensor dimension is determined by the physical sensor dimension and projection distance.

Here d is the relevant sensor dimension and v is the projection distance in the same units. Photivra uses nominal focal length for its infinity-focus compatibility mode. When a focus distance is supplied, it can use the ideal Gaussian thin-lens image distance instead.

What changes field of view?

• A larger sensor dimension increases field of view for the same projection distance.
• A longer focal length narrows field of view.
• At closer focus distances, the ideal thin-lens image plane moves slightly farther from the lens, changing projected scale.

Model limits

This is ideal rectilinear, paraxial geometry. It does not model real-lens distortion, focus breathing, principal-plane movement, or lens-specific macro behavior.