The image offered by Zeiss Standard Prime T2.1 lenses is purely Zeiss. From T2.8, they offer an absolutely modern, clean and detailed image, with the hard cut that characterizes the manufacturer and similar to that of later designs such as the Ultra Prime. Only its lower contrast and resolution, noticeable more in a letter than in reality, betrays the differences. That is why at T4 or T5.6 it is difficult to appreciate what are the T2.1, the T1.3 or the Ultra Prime.
However, what makes these lenses very interesting, whose design is also very compact, is that more open than T2.8, the image is more “vintage”: the contrast and resolution are reduced and the vignetting is much more noticeable , especially in T2.1, although the greatest defects logically appear when the T1.3 is fully open. They are therefore very interesting and highly appreciated lenses, since they have double characteristics and personalities, without being as old or as modern as other series.