Leica - APO Summicron ASPH - SL F2 / 90mm - Black

Its high speed and the unique aesthetics of its depth of focus make this telephoto lens the first choice for portrait photographers. At the decisive moment, its almost silent and simultaneously precise autofocus gives photographers more time to concentrate fully on the creative aspects of their subject, the person in front of their camera. Like all Leica SL-Lenses, the APO-Summicron-SL 1:2/90 ASPH. is perfectly matched to the modern SL-System and is constructed for a long working life under professional shooting conditions.

 

AF System with Dual Syncro Drive™
From zero to sharp in no time

 

The AF system of the Summicron-SL lenses is fast, precise, and almost silent. They thank their outstanding AF performance figures to the autofocus drive unit they share. These are limited only by the mass of the lens elements moved when focusing, the travel from infinity to the closest focusing distance and, of course, the amount of space available. In order to preserve the compact dimensions of the lenses, the integration of these components must follow an integral approach.

 

Higher Contrast
for greater perceived depth

With an initial aperture of f/2, the SL-Summicron lenses are significantly more compact than faster lenses, but still allow photographers to work with similar depth of field. The reason for this is contrast: the zone of highest contrast is perceived by viewers as being sharp, while zones with lower contrast are regarded as being unsharp.

Optically and Mechanically
a new standard

In the construction of the Summicron-SL lenses, particular attention has been paid to the prevention of stray light and reflections. The optimization of the optical and mechanical design was carried out in elaborate simulations before the construction of the first prototype lenses. Unavoidable reflections are reduced to the best possible level by high-quality coating of lens surfaces.

Complex Electronics
for uncomplicated handling

The three most obvious functions of a Summicron-SL lens to users – focusing, MF ring, and aperture setting – are all based on a multitude of control systems and mathematical operations. The demands on the electronics are particularly high in the case of the double focusing system. Here, the two autonomous focusing units must be moved in perfect synchronization and positioning data have to be analyzed at a very high sampling rate and passed on to the camera.