ENB Series - loss of sharpness

Can anyone explain why when I enable the ENB Series mod I experience a loss of sharpness to the whole display? I use the SUPERCAA 64x_4v12 setting. Without ENB Series enabled I have wonderfully crisp image quality. When enabled the whole thing looks as though it has been slightly softened. This effect does not occur if I use 8xS or 16xS antialiasing, but I much prefer to use 64x_4v12 as the sim looks better and runs smoother for me on this setting. Is there any way of avoiding this effect?