Scope Optics Reality; They're All Focal Systems. One At Each End.
Virtual images need lenses to create them by focusing near parallel light rays from each point of the target to converge back to a single point. If those light rays don't meet at one point, the image will be blurred and fuzzy at its intended plane.
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Where did those two images in post #2 come from?
The virtual image presented by an afocal instrument may be view by an eye or photographed by a camera but it cannot be projected such as onto a screen.
Virtual images cannot be made unless light rays from something are focused (converged) to a single point. Lenses do that.
If a virtual image can be seen or photographed, it can be projected onto a screen. All three systems are identical in the way an image is focused on an eye retina, film or screen. Only difference is the focal lengths of the lenses and the distances between each three parts.
Optical engineers use formulas to calculate lens focal lengths and their positions in the scope for mechanical engineers to design the scopes lens mount positions and their mechanical adjustment ranges. Lens makers mold, grind then coat and sometimes cement them together to meet size and focal length requirements. Instrument machinists make the mechanical parts.
A rifle scope's front objective lens focuses (converges) diverging light rays from the target to a virtual image behind it at the 1st image plane. If it's a 7" focal length and target's at a 1000 yards, a virtual target image is 7.001361" behind it. Focused on a 100-yard target, that virtual image is 7.013638" behind it. Exact same optical principals of a camera with a 177.8028mm (7 inch) lens.
That scope's erector lens group's focal length is what's needed to converge the 1st inverted virtual image plane's diverging light rays to focus and converge them on the reticle at the 2nd image plane as a virtual, twice inverted target image. Exact same optical principals of a camera with a lens with a fraction of an inch focal length.
An eyepiece lens behind the reticle and 2nd image plane has a focal length equal to its distance back from that plane. It converges the diverging light rays from that 2nd image plane to near parallel paths best suited to the aiming eye properties. The aiming eye sees that now magnified image of the target as the eye lens focuses those light rays to converge its image inverted on the retina. Another optical system like cameras have. The human brain inverts it upright.
Scope magnification is equal to its objective lens' focal length divided by the optical focal length of the erector and eyepiece lenses combined. If the scope objective lens has a focal length of 7 inches and its power is 10X, the optical focal length of those combined lenses behind the 1st image plane is 7/10ths inch. If the scope's 16X, those combined lenses focal length is 7/16ths inch.
Human eyes' concave retina compensates well for its lens focus field curvature. Image sharpness is virtually equal over its 120 to 150 megapixel rod-cone sensors. Focused image distance is virtually the same for its sensors for all viewing distances.