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.
The Coddington loupe is not color corrected, however, and so we caution against using it for grading gems or in other applications which require a color corrected loupe. The Hastings Triplet Loupe is a color corrected loupe.
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.
1 inch working distance
25,4 mm lens diameter
.8 inch working distance
20 mm lens diameter
.5 inch working distance
13 mm lens diameter