Asking for a physical knowledge is a table, which is about the image distance of U > 2f. ...

Supplement to the law of imaging: into a real image: the smaller the object distance, the greater the image distance and the larger the real image.

Virtual image: The smaller the object distance, the smaller the image distance and the smaller the virtual image.

The real image is upside down and the virtual image is upright.

Supplement: 2f>u>f

Inverted magnified real image

Projector, slide projector, projector

u & gt2f

The true image of reverse reduction

Cameras, video cameras

u=f

No imaging

Parallel light source: searchlight

Lens imaging satisfies the lens imaging formula:

1/u (object distance)+1/v (image distance) = 1/f (lens focal length)