The Leica APO-Macro-Macro-Elmarit-R 100mm f/2.8 was a ground breaking lens when it came out in l987. It is still a lens worth exploring on the Leica M with Live View, the Leica SL or any other modern digital camera.
As Leica APO lenses usually are, the 100mm APO-Elmarit-R f/2.8 has very good colors and details.