| This filter blocks the invisible UV parts which might cause unsharpness. |
| Unsharpness and resolution refer to the degree of blurring along the boundaries between different regions of the image. |
| In the majority of cases, though, unsharpness is caused by shutter speeds that are too slow. |
| The allowable amount of unsharpness is controlled by specification being followed. |
| This article describes a method not just to measure wide angle unsharpness but also to adjust the lens precisely with the film running. |
