#image sharpness
- Anastigmatic — Free from astigmatism; optimally corrected from a geometric and optical standpoint to eliminate asymmetric convergence aberrations of oblique light rays. It is applied to systems, lenses, aspherical surfaces, or light beams capable of forming a perfect point-like image of a point object, offering exceptional flatness of the visual field.
- Anastigmatism — An ideal optical property or characteristic of a lens or mirror system being completely free from astigmatism; the absence of asymmetric focusing distortions, allowing oblique light rays passing through the system to converge into a single precise focal point. This structural phenomenon guarantees uniform sharpness and an exceptional flatness of the image across the entire surface of the projection plane, eliminating marginal blurring.