The new Sony FE 1.4/50 mm GM has a higher contrast than the Zeiss Planar T FE 1.4/50 mm ZA. This is most evident at open aperture and there also with the edge fall-off. The Sony GM weighs only 516 grams instead of 778 grams like the Zeiss optics and is one centimetre shorter. So the Zeiss Planar remains a very good lens, but has to give way to the new, even better Sony GM in terms of image quality...