这种叫
Barrel Distortion。傻瓜机上这种毛病比较普边。
Barrel DistortionBarrel distortion is a lens effect which causes images to be spherised
or "inflated". Barrel distortion is associated with wide angle lenses
and typically occurs at the wide end of a zoom lens. The use of
convertersoften amplifies the effect. It is most visible in images with perfectly
straight lines, especially when they are close to the edge of the image
frame. See also the opposite effect,
pincushion distortion.