APO-Summicron-SL 50 f/2 ASPH.

Sharpen your visual perspective

Over a century of passion for photography is brought together in the new APO-Summicron-SL 50 f/2 ASPH. to create a new dimension of visual acuity. Its unique combination of the highest detail rendition and a focal length that gets closest to what is naturally perceived by the human eye delivers especially ‘authentic’ results. Perfectly matched to the state-of-the-art SL-System, with one of the fastest autofocus systems in the professional camera segment, the APO-Summicron-SL 50 f/2 ASPH. captures the essence of special moments in a flash with razor-sharp fidelity.

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

The autofocus system shared by the Summicron-SL lenses is fast, precise, and nearly silent. Their outstanding AF performance figures are thanks to the autofocus drive unit they both utilize. These are limited only by the mass of the glass elements moved when focusing; the speed of moving from infinity to the closest focusing distance. In order to preserve the compact dimensions of the lenses, the integration of these components must be perfectly optimized within all design constraints. 

More Details

Specialists from the areas of optical engineering, mechanical engineering and electronics worked together as an interdisciplinary team on the development of a unique lens concept based on double internal focusing. This system, comprising two especially light focusing lenses, allows the construction of particularly small and compact drive systems. While being able to work within tight space constraints, the drive motors used must maintain peak performance in all situations to be chosen for such a cutting-edge camera system.

Several contrast measurements at various focusing positions must be made before the correct direction for focusing can be determined and followed by precise focusing. In this procedure, the focusing lens elements must be moved rapidly in accordance with the speed specifications of the contrast AF system. This requires a dynamic drive system without any room for error.

In the Summicron-SL lenses, the drive units installed are extremely powerful and robust stepping motors with Dual Syncro Drive™. Thanks to these, the entire focusing range can be traveled completely in fractions of a second. This means that the Summicron-SL lenses achieve values that are among the best in the full-frame system segment in terms of speed, precision, and operating noise. 

Higher Contrast
for greater visual depth

With a maximum aperture of f/2, the SL-Summicron lenses are significantly more compact than even faster lenses, but still allow photographers to work with similar depth of field. The reason for this is contrast: the area of highest contrast is incredibly sharp, while zones with lower contrast are unsharp or beautifully blurred.

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In the case of SL-Summicron lenses, this difference in contrast is considerably higher than that of conventional lenses: sharply focused objects show much higher contrast than objects that are out of focus. This means that objects “pop” more distinctly out of the foreground or background and more effectively isolate the subject. This creates a three-dimensional visual effect with very impressive depth.

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 lowest possible level by high-quality optical coatings of the lens surfaces.

Complex Electronics - Asset 1
Complex Electronics - Asset 2
Complex Electronics - Asset 3

Complex Electronics
for uncomplicated handling

The focusing and aperture setting functions of a SL-Summicron lens are based on a multitude of control systems and mathematical operations. The demands on the electronics are particularly high in the case of the dual-synchro drive focusing system. 

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The two autonomous focusing units must be moved in perfect synchronization and positioning data must be analyzed at a very high sampling rate and passed on to the camera. Here, the communication with the camera is so fast that there is no perceptible delay. These are the primary preconditions for fast and precise contrast autofocus.

The aperture is driven by a stepping motor. Here, a special micro-step control system ensures precise and fast movements with minimized vibration.

Manual Focusing
A new experience

SL-Summicron Lenses feature a totally new manual focusing ring construction concept. In this concept, a ring magnet with alternating north-south magnetization is embedded in the manual focusing ring. The magnetic field changes its polarity when the ring is turned. 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.

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The construction of the manual focus ring guarantees reliable sealing against dust and water spray, provides protection against impacts and other mechanical stresses, and prevents focusing inaccuracies as a consequence of temperature fluctuations. Even after years of use, the manual focus ring of a SL-Summicron lens maintains a smooth action without play and homogeneous focusing.

Impressive
down to the smallest detail

The consistently compact dimensions, low weight, and the excellent grip and feel of the SL-Summicron lenses are particularly impressive when shooting. Thanks to the almost identical design of the Summicron-SL lenses, each one handles nearly identically and the center of gravity remains largely the same. This means that the camera always lies perfectly in the hand and makes working from a tripod much easier. 

Proofs of performance
APO-Summicron-SL 50 f/2 ASPH. in action

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Technical Data

APO-Summicron-SL 50 f/2 ASPH.

Download (pdf/805.29 kB)

Order number 11 185
Field angle (diagonal, horizontal, vertical) 47.2°/40°/27.3°
Optical design
Number of lenses/groups 12/10
Number of asph. surfaces / lenses 4/3
Entrance pupil position 63.2 mm at ∞
Distance setting
Working range ∞ to 0.35 m
Smallest object field 120 x 180 mm
Largest reproduction ratio 1:5
Aperture
Setting/function Electronically controlled aperture, set using turn/push wheel on camera, including half and third values
Aperture setting range 2 - 22
Lowest value 22
Bayonet/sensor format L-Mount, full-frame 35 mm format
Filter mount E67
Dimensions and weight
Length to bayonet mount 102 mm
Largest diameter 73 mm
Weight 740 g

Constructional Details

What makes the APO-Summicron-SL 50 f/2 ASPH. so special is an optical system comprising of 12 lens elements produced with unique expertise and the latest manufacturing technology by Leica. Of these, three elements with four aspherical surfaces correct monochromatic aberration, while eight elements manufactured from specially formulated, high-quality glass types ensure chromatic correction throughout the entire focusing range. Only the particular optical property of these glass types, known as anomalous partial dispersion, makes it possible to compensate for chromatic aberrations with such perfection. As a consequence of this, even highlights in images remain almost completely free of color fringing.

Place your order now:
APO-Summicron-SL
50 f/2 ASPH.

The next step on your photographic journey is only a click away: make the decision now, and raise your art of photography to an entirely new level.

Find a store

Name Order number
Lens Hood for SL 50 f/2 ASPH., 75 f/2 ASPH. and 90 f/2 ASPH. 12302
Lens cap SL 16045
Lens rear cap SL 16064
Filter ND 16x E67, black 13071
Filter UVa II, E67, black 13040
Filter P-cir, E67, black 13049

L-Mount
A new era of creative freedom

The L-Mount marks the start of a new era of lens compatibility without compromise. Never before has one lens mount standard allowed for an almost limitless array of options in combining different interchangeable lenses with cameras featuring different sensor formats.

With the alliance between Leica Camera, Panasonic and Sigma, a collective 250 years of experience in the field of lens and camera construction will be combined into one platform. For the photographer, this opens up the chance to utilize endless variations of camera-lens combinations from the extensive product portfolios of all three manufacturers, allowing them to always find the best solution for their needs and any photographic situation.

Find out more at www.l-mount.com

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