Like Plano-convex lens, double convex lenses have positive focal lengths and form both real and virtual images. Symmetry is assured by finishing both surfaces with the same tool. Because of symmetry, aberrations including coma, distortion and lateral chromatic aberration almost exactly canceled at unit conjugate radio. Double convex lenses have shorter focal lengths than Plano-convex lenses of equal diameter and surface radius.
| ATTRIBUTE | SPECIFICATIONS |
| DIAMETER TOLERANCE | +0.1, -0.1mm |
| thickness tolerance | +/-0.1mm |
| CENTRATION | 3 arc minutes |
| CLEAR APERTURE | >90% |
| radius | +/-0.1% |
| SURFACE FIGURE: POWER(N) | <3 fringes |
| SURFACE FIGURE: IRREGULARITY(N) | <0.5 fringe |
| SURFACE QUALITY | 40/20 scratch and dig |
| BEVEL | < 0.2 mm x 45° |
| COATING | With or without AR coating on outside surfaces |
