This optional accessory is designed to work strictly with the EF 50mm f/2.5 Compact Macro lens. Unlike typical life-size adapters, the Life Size Converter EF actually has optics that is optimized for high magnification when combined with the 50mm macro lens. Magnifications from 0.26x (approx. 1/4 life-size) to 1.0x (true life size) are possible, at increased working distances.