The Cokin Split Field +3 filter consists of a close-up lens cut in half. Half of the filter is a close-up lens while the other half is open. In this way, it is possible to have both very close and far subjects in focus at the same time or one-half of the picture can be out of focus for special effects. This application is commonly used for floral and landscape photography where sharpness near and far is important. By turning the filter you determine what is close and what is background.