What negative visual effect is caused by curvature of field?

Curvature of field refers to a distortion that occurs in optical systems, where the image does not focus to a flat plane, leading to certain areas of the image appearing sharp while others are blurred. This effect typically manifests at the edges of an image, resulting in the edges appearing less defined or blurry compared to the center of the image, where focus is generally best. This blurry edges phenomenon is particularly notable in wide-angle lenses or systems that are designed to cover a large field of view.

The other options relate to visual effects that are not primarily caused by curvature of field. Increased contrast, for instance, pertains to the difference in luminance or color that makes an object more distinguishable, but is not a direct consequence of lens distortion. Oversaturation involves an excessive richness of color that can occur through different processing techniques or in specific lighting conditions, but is not tied to the optical characteristic of curvature. Color distortion, while it can result from various factors in imaging systems, does not specifically arise from curvature of field in the way that fuzzy or blurry edges do in a lens system. Thus, the primary negative visual effect linked to curvature of field is the presence of blurry edges.