One of the few lenses I've observed that transmits all the light -- and the information that light carries, to the sensor or film plane. Its maximum aperture value is equal to its T-stop value. F1.4 = F1.4, this according to DXOmark. Very sharp by f2.8, and razor sharp by f5.6 and beyond.
F stop value = T-stop value no light absorbed by adding too many light/information absorbing elements: 1.4 = 1.4; a true "f1.4" lens; sharpness; cost; brilliant image quality; size; weight; cost; durable in-camera screw drive auto focus (not tiny in-l
Some have said there is a hot-spot in the center of the frame at f16, which is especially evident shooting IR film; I have briefly tested for this on my digital camera and did not observe this; But I rarely shoot f16 and have not shot any IR film in a dec