This ultra-wideangle lens provides great depth-of-field and emphasizes perspective. Its rear-focusing system ensures quick, precise focusing and corrects close-focus aberrations. Its rubber focus ring provides comfortable manual focusing operation. Lens construction: 10 elements in 9 groups Angle of view: 94 degrees Minimum focusing distance: 0.8 foot Minimum F/stop: F/22 Filter size: 72mm Weight: 10-1/16 oz. Lens construction: 10 elements in 9 groups Angle of view: 94 degrees Minimum focusing distance: 0.8 foot Minimum F/stop: F/22 Filter size: 72mm Weight: 10-1/16 oz.