50mm This is a very good goal !! Having acquired at Christmas I could test it in all its seams. It is excellent in low light conditions. (In a church when you open at f / 1.4, the exposure time is 1 / 80s with the lowest ISO !!!) The sharpness is fabulous to f / 1.4 but to have the best of it must be f / 1.8, especially for the Macro. For maximum aperture portrait widely enough. It is a very versatile lens, excellentissime for the portrait. It is made for beginner photographers in the middle or photographers who want to confirm that pleasure. The price of the latter is fully justified given the great qualities offered by it. The only downside I could find is the development which sometimes is a bit temperamental, but this defect is soon forgotten by its many advantages. It's a goal that I highly recommend !!!