The APO-Summicron-SL 28mm f/2 ASPH. combines a classic wide-angle focal length with state-of-the-art technology. The 28mm focal length allows for a sharp overview from edge to edge without distorting the perspective too much. The ability to separate the focal plane without loss of performance by using an open aperture provides even more extensive creative possibilities.
With the addition to the ever-expanding APO-SUMMICRON-SL series, Leica presents yet another high-performance wide-angle lens for the Leica SL-System. The APO-SUMMICRON-SL series is a lens range that is renowned for its top-level optical performance and extremely fast and reliable autofocus. Following the existing focal lengths of 35, 50, 75 and 90 mm, the APO-Summicron-SL 28mm f/2 ASPH. is the first true wide-angle lens in this series. All APO-Summicron-SL lenses feature the exact same dimensions and, consequently, the same filter size. Its angle of view makes the APO-Summicron-SL 28mm f/2 ASPH. especially suitable for reportage, interior and architectural photography. Its maximum aperture – which is large for this focal length, yet can be used without any loss of image quality – offers additional creative possibilities through the controlled application of sharpness and blur. Thanks to the L-Mount standard, the APO-Summicron-SL 28mm f/2 ASPH. is equally compatible with cameras made by other partners of the L-Mount Alliance that have been equipped with the Leica-developed lens mount.
13 lens elements (three of which feature aspherical surfaces on both sides) in ten groups contribute to a maximum level of image quality even at wide open aperture. As is generally the case with Leica lenses, the maximum aperture is synonymous with the effective aperture. Consequently, there is no need to stop down to increase the image quality – instead, reducing the aperture is only necessary for compositional purposes. Natural skin tones, soft transitions into bokeh, exceptionally contrast-rich details and edge-to-edge sharpness across a distortion-free image: these qualities are very much the norm for Leica lenses. Yet the APO-Summicron-SL 28mm f/2 ASPH. is further distinguished by its apochromatic correction, which is a notable feature in a lens of this focal length. To ensure the optimal correction of chromatic aberrations, the majority of the grouped lens elements feature anomalous partial dispersion, and are made of high-quality, specialist glass types whose construction is so elaborate that even Leica’s innovative production methods are utilized to within every last inch of their capacity.
The autofocus drive of all Summicron-SL lenses employs extremely robust and high-performance stepping motors with DSD® (Dual Syncro Drive™). This enables the AF to travel the entire focusing range in around 250 milliseconds. At the same time, Leica Camera also takes an innovative approach to manual focusing technology: Summicron-SL lenses feature an entirely new manual focus ring construction in the form of an embedded ring magnet with alternating north-south polarization. When the ring is turned, the magnetic field changes its polarity. A sensor monitors the status of the magnetic field and sends the data to the main processor. The drive then shifts the lens to the corresponding focusing position on the basis of the angle of rotation and the rotational speed – this, in turn, enables even faster and more precise manual focusing.
Both the construction and the design of the cutting-edge Summicron-SL series represent the next step forward in the development of lenses for the Leica SL-System. New, extremely precise manufacturing methods and measuring technologies have been developed specifically for the production of these lenses – resulting in more compact dimensions and a considerably lower weight, as well as a truly outstanding imaging performance. In the construction of the APO-Summicron-SL lenses, particular attention has been paid to the prevention of stray light and reflections. In addition to optimising the optical and mechanical design, the developers also reduced unavoidable reflections to an absolute minimum by applying a high-quality coating to the lens surfaces. Thanks to their effective sealing against dust, moisture and water spray, as well as the Aquadura coating of the exposed lens surfaces, these extremely durable lenses can be used in almost all weather conditions without any reason for concern.