12.5" Diameter, 23" Focal Length, Fresnel Lens

Fresnel lenses are composed of a series of concentric grooves etched into one side of a sheet of plastic. Fresnel lenses are unlike typical spherical or aspherical optical lenses.

When doing basic imaging, how do you determine the magnification an optical lens will provide?

Although a common misconception, individual optical lenses do not always form an image when the object plane is placed a focal length away from the lens.