The Canon EF 50mm f/2.5 Compact Macro and the Life-Size Converter EF (now discontinued). The LSC allows the 50mm macro to get to 1:1 with a larger working distance. Without it, it only reaches 1:2. It will also reach 1:1 with a 25mm extension tube but the working distance gets very short. The magnification marks on the barrel are with the LSC attached. The magnification marks on the distance scale are for the bare lens.
The LSC has extra contacts to match the lens so that the EXIF reads as a 70mm f/3.5 lens when attached. The LSC is actually a 1.4x teleconverter combined with a 12mm extension tube. Any EF lens can be physically mounted (not EF-S however) but it only communicates with the 50mm f/2.5. Canon includes the LP811 pouch in the LSC package.








