This 4 x 5.65" +1-strength Diopter from Simmod is particularly useful for close-up shots that require greater magnification and a shallow depth of field. Diopters are most effective with anamorphic lenses but can also be used with spherical lenses. This +1-strength diopter is crafted with a 14-layer double-sided nano coating and has been mounted in a custom aluminum 4 x 5.65" frame for use in popular matte boxes. For greater ease of operation, a red anodized handle has been mounted on the side or top of the tray when using a side-loading matte box. This diopter requires two filter slots without dividers. If your matte box has a divider between slots, this diopter will not fit.