The two most important parameters in objective design are the numerical aperture (which determines the fine detail in the image) and the magnification, which decreases the area that is imaged. For more than 100 years the magnification of objective lenses was kept between 40 and 70 times the numerical aperture. It was thought pointless to make this number lower, since, even though a larger field could in principle be seen the detail in the image would then be too fine to be seen by the human eye.
The Mesolens has a magnification-to-N.A. ratio of 8, achieved by a total redesign, in which great precision is required to achieve the correction of chromatic and other aberrations. This was made much more difficult by the need to use large optical elements (its magnification is x4 and NA 0.5 and working distance nearly 3 mm, multi-immersion): aberrations scale with the diameter of the ...
