There are three versions of the first generation Summicron 90mm f/2 with the same optical design, differing mainly in appearance. They are also all very well built, focus smoothly, and have been defined as high-end lenses from the start. These lenses are mainly used by professional photographers for portraits and long distance work. They have excellent optics and their only drawback is that they are too bulky.
The design of the built-in hood is very clever. I really like this design. The mechanical design of the hood is also very good, and the push and pull damping is perfect. I have not seen any other lens with such perfect damping, including later Leica lenses.
For the Leica m camera system, there are two major problems with using a 90mm lens: the field of view is too small and the focusing speed is too slow. Another major problem is hand shaking. The safety shutter of a 90 mm lens is 1/100s. Shutter speeds below that are prone to hand shake. This greatly reduces the frequency of use.
SEOOF-M
Maximum aperture: 1: 2 Angle: 270 Minimum distance: 100cm Filter: E48
