These high-quality single element close-up lenses require absolutely no exposure compensation. The Schneider 4.5 Diopter Lens feature hard, anti-reflective coating on both front and rear surfaces. This measurably reduces light loss and flare while helping to ensure proper color, contrast, and overall image quality. Schneider drop-in diopters feature rugged black anodized aluminum rings. The diopters are protected by a unique mounting technique which ensures superb structural integrity and consistent long-term performance, even in the harshest production environments. Diopters can increase the minimum working distance enabling closer focus from a greater working distance. Calculation of strength depends on focal length, focus setting, object distance, and size.