What does Focal Front Flat Field Architecture mean?

What is Flat-Field eyepieces ?

Flat-Field eyepieces is an upgraded function of ordinary eyepieces, that uses La Lanthanide Optical lens, Through low-speed polishing, it is processed into double cemented lens. The advantages of Flat Field eyepieces are smaller chromatic aberration, higher brightness, and clear and sharp image. The most important point is the distortion from the center of the image to the edge, Compared with finished products processed by ordinary optical lens, the distortion is small, the image surface is flatter, and all are called Flat Field eyepieces. Some of our high-end binoculars,monocular telescope, spotting scope series also use flat field eyepiece, which cost more, but it's better quality.

Focal front flat field architecture uses "second generation" focal front flat field technology, Field curvature, distortion, and phase attenuation have been improved, and the center to the edge of the field of view is sharp and clear.
The focal front flat field architecture is on the focal plane or near the side of the objective lens in front of the focal plane, where places a set of flat field lenses to improve the field curvature, make the image surface flat, and make the edge imaging the same as the center imaging, to increase the good image range, make the imaging center sharp to the edge.

As the "first generation flat field eyepieces" has defects that are prone to black spots in imaging, our factory has made improvements and solved the problem, and applied to our high-end binoculars, monocular telescope,spotting scope series.