| Answer | Crossword Clue |
|---|---|
| aplanatic | of a lens, free of spherical aberration |
| aplanatically | APLANATIC, of a lens, free of spherical aberration |
| fresnels | A flat lens made of a number of concentric rings, to reduce spherical aberration |
| apochromatic | free from chromatic and spherical aberration |
| distortion | aberration of objects seen through a lens or system of lenses |
| lenticule | one of many tiny cylindrical or spherical lens segments embossed on the surface of a film used in stereoscopic and color photography |
