Split Diopters are an incredible tool that help you enhance depth-of-field. They allow for more of the scene to be in total focus simultaneously. These diopters are semi-circular pieces of glass that are mounted in ring form. They can be rotated in a Matte-Box to achieve the desired effect.
The Schneider Split Diopter +1/2 Filter – 138mm is used to increase the minimum working distance, enabling closer focus. These special diopters differ from traditional diopters in that the single diopter element is cut in half and mounted in the ring. Therefore, half of the image is magnified and the other half is untouched.
Split Diopters are perfect for scenes where 50% of the frame requires close focus and the other half requires distant focus, while keeping all points in-between sharp. Spilt Diopters are available in strengths of +1/2, +1, +2, and +3.