It sets new standards in the medium telephoto range of the LEICA-R SLR system. The aspherical lens surface is ground by new computer-controlled CNC machines. Due to the necessary size of the lens element, this demands considerable technological know-how for the grinding and polishing process.
Together with two high-refractive glass elements, the aspherical element is responsible for the lens's small size and light weight. The remaining two of the total of five lens elements have a special refraction property (high anomalous dispersion) with which the short- and long-wavelength components of the light are especially closely recombined. This results in outstanding contrast and exceptional definition.

The residual chromatic aberrations that occur at long focal lengths and high speeds are effectively avoided by the apochromatic correction. Even pictures with extremely fine structures show no color fringing.
The imaging quality is consistently high and homogeneous over the whole image field even at full a per ture and can only be enhanced slightly by stopping down a stop.

The brilliance and resolution of the new LEICA APO-SUMMICRON-R f/2/90 mm ASPH. are superb. Distortion is so slight that it is practically undetectable even in difficult subjects. The artificial vignetting is extremely small and disappears completely from f/4 onwards.

The highest optical performance starts at medium distances already and is largely retained even in the close-up range.
The built-in telescopic lens hood can be locked in its extended position by rotation. The filter thread size is E60.