APO-Summicron-SL 50 f/2 ASPH.

Anything but a standard lens

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 aesthetics. Its unique combination of 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, and 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 remarkable pictures.

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.

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Specialists from the areas of optical and mechanical engineering and electronics worked together in an interdisciplinary team on the development of a unique lens concept based on double internal focusing. This system, comprising two particularly light focusing lenses, allows the construction of particularly small and compact drive systems. In addition to space limitations, the choice of the drive motors is also determined by the AF principle used for focusing.

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

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 throw 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 noise emissions. 

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.

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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 “snap” more distinctly out of the foreground or background and more effectively isolate the subject. This creates a three-dimensional visual effect with very impressive apparent 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 best possible level by high-quality coating of 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 double focusing system. 

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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. 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 AF.

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 MF-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 MF-ring of a SL-Summicron lens impresses with 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, feeling for the MF ring is unnecessary after switching lenses 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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1/800
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2
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1/640
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6.3
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1/125
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Technical Data

APO-Summicron-SL 50 f/2 ASPH.

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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 know-how and 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 colour fringing.

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

The fulfillment of photographic dreams is often only a click away: make the decision now, and raise your art of photography to an entirely new level.

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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 combined 250 years of experience in the field of lens and camera construction will be consolidated in one platform. For the photographer, this opens up the chance to compile endless variations of camera-lens combinations from the extensive product portfolios of all three manufacturers, and so continually find the best solution for any photographic situation.

Find out more at www.l-mount.com

Perfect matches.
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