Coddington magnifiers achieve correction through the use of a single thick lens with a central groove diaphragm, which provides sharp, crisp images.

The Coddington magnifier made up of a single lens in a very sturdy black plastic enclosure, which is itself enclosed by a folding nickel-plated case. The fact that the magnification comes from a single lens makes this a perfect magnifier for outdoor use, as it will not be damaged by exposure to water.

The thick lens has a equatorial groove around it which is coated black. The groove effectively eliminates spherical aberration, which is a kind of distortion of the image. Because of this correction, the image you see is sharp, crisp and clear.

While a Coddington loupe has a wider diameter than a Hastings Triplet Loupe, the viewing area is actually smaller because of the black coating on the equitorial groove. The viewable lens portion of a Coddington is approximately 60% of the lens diameter.