As a slightly wide-angle standard focal length, the application possibilities of the APO-Summicron-SL 1:2/35 ASPH. are almost unlimited. With its fast autofocus, robust design and outstanding image quality, it is ideal for reportage photography, but also impresses in other areas such as architecture, landscape and portrait photography as well as studio use. It is perfectly adapted to the modern SL system and has been developed for a long service life under professional conditions.
AF system with Dual Syncro Drive™ - from 0 to sharp in a fraction of a second
The autofocus of SL-Summicron lenses is fast, precise and quiet. The drive unit determines the AF performance data. These are limited by the weight of the focus lenses, the stroke from infinity to the close-up range and, of course, the available space. In order to maintain the compactness of the Lens, these components must be integrated in a holistic approach.
An interdisciplinary team of optics, mechanics and electronics developers has developed a unique lens concept based on double internal focusing. This system, consisting of two particularly lightweight focus lenses, allows the use of small and compact drive systems. In addition to the spatial restrictions, the choice of drive motors is also determined by the AF principle.
In order to determine the correct focusing direction and then focus precisely, several contrast measurements are required at different focus positions. To do this, the focus lenses must be moved back and forth quickly in accordance with the speed specifications of the contrast AF system. This requires a dynamic drive without backlash.
The SL-Summicron Lens uses extremely powerful and robust stepper motors with Dual Syncro Drive™ as drives. With these, the entire focusing range can be traversed in a few fractions of a second. As a result, the SL-Summicron lenses achieve the best values among full-frame systems in terms of speed, precision and noise emission.
More contrast for more depth of field
With an aperture ratio of 1:2, the SL-Summicron lenses are much more compact than even more light-sensitive Lens, but allow you to work with a similar depth of field. The reason for this is the contrast: the viewer perceives the zone of highest contrast as sharp, while the area with a lower contrast in comparison is blurred.
With SL-Summicron lenses, this difference in contrast is much greater than with conventional lenses: Focused objects have a higher contrast than unfocused objects. As a result, objects stand out more from the foreground or background. The subject can be better separated. The result is a three-dimensional image impression with a very impressive depth effect.
Optically and mechanically - a new standard
When designing the SL-Summicron lenses, particular attention was paid to avoiding stray light and reflections. The optical and mechanical design is optimized before the prototypes are built by means of complex simulations. Unavoidable reflections are reduced to the best possible level through high-quality coating of the optical surfaces.
Complex electronics - for uncomplicated handling
The focusing and aperture setting of an SL-Summicron Lens are based on a large number of control and computing operations. Double focusing in particular places high demands on the electronics.
The two independent focusing units must be moved absolutely synchronously and the position data must be evaluated at a very high frequency and passed on to the camera. Communication with the camera takes place so quickly that there is no perceptible delay. These are the basic prerequisites for fast and precise contrast autofocus.
The aperture is driven by a stepper motor. Special control in microsteps ensures precise, fast, smooth and low-vibration movement.
Manual focusing - a new experience
SL-Summicron Lens use a new type of manual focus ring design. A ring magnet with alternating north pole-south pole magnetization is embedded in the ring. If the ring is rotated, the magnetic field changes. A sensor evaluates the magnetic field and sends its measurement signals to the main processor. Depending on the angle and speed of rotation, the focus position is adjusted accordingly.
Convincing - down to the smallest detail
In use, the SL-Summicron lenses impress with their uniform compactness, low weight and excellent feel.
Thanks to the almost identical design of the SL-Summicron lenses, there is no need to feel the MF ring again after a lens change and the center of gravity is largely retained. This means that the camera always sits perfectly in the hand and handling on a tripod is also made easier.
Construction in detail
The APO-Summicron-SL 1:2/35 ASPH. is made up of 13 lenses. Three aspherical lenses were used to correct monochromatic aberrations. To avoid chromatic aberrations, 9 of the 13 lenses are made of high-quality special glass, which can only be processed using the latest manufacturing methods. Their special optical property, known as anomalous partial dispersion, makes it possible to compensate for chromatic aberrations in the overall system. As a result, even highlights in the image are free of color fringing
L-Mount - A new era of creative freedom
The L-Mount marks the beginning of an era of uncompromising compatibility. Never before has a lens bayonet allowed almost unlimited combinations of interchangeable lenses from different systems with cameras of different sensor sizes.
With Leica Camera, Panasonic and Sigma, three brands from the photography industry are combining more than 250 years of technological experience, expertise and know-how in the construction of cameras, optics and photographic solutions on one platform. For the user, the alliance opens up the opportunity to put together the best solution for every conceivable application situation from the extensive portfolio of Leica Camera, Panasonic and Sigma.
