This is the most popular Telephoto lens for the Leica R system. The Lens is small, easy to carry & handle, very sharp & contrasty and Fast enough for most situations. The 90mm Elmarit has an outstanding reputation and is perfect for portraits as well as scenics when you want to get in a little closer to fill the frame. It was produced in two versions with two different optical formulas. The first version utilized 5 elements in 4 groups, while the later version utilized 4 elements in 4 groups. This lens is also great for close ups. With the addition of the Elpro, a magnification of 1:3 is produced which will fill the frame with most subjects. The lens also has a flat field by design, lending itself well to macro photography. This is a very verstile lens.