LEICA APO-SUMMICRON-M 50 mm f/2 ASPH.
LIAA
1
More than 30 years after the launch of Summicron-M 1:2/50 mm, which is still available, the Leica APO Summicron-M
1:2/50 mm ASPH. represents a totally new development. With its compact body - only marginally longer and slightly heavier than
the Summicron-M 1:2/50 mm, and with an almost identical diameter, it provides visibly higher image quality. On the Leica APO
Summicron-M 1:2/50 mm ASPH. the exceptional correction enables all aberrations to be reduced to a minimum level that is negli-
gible in digital photography. Its key features include excellent contrast rendition, all the way to the corners of the image, even with
a fully open aperture. The use of a „floating element“ ensures that this is retained, even for close-up shots. Vignetting is limited to
a maximum - i.e. in the corners of the image - of just 2 stops at full aperture in 35 mm format, or around 1 on the Leica M8 mo-
dels. Stopping down to 2.8 visibly reduces this light deterioration towards the edge of the image, with practically only the natural
vignetting remaining. Distortion is very low at a maximum of just 0.4 % (pin cushoin), which is practically imperceptible. A total of
eight lens elements are used to achieve this exceptional performance. To realize the apochromatic correction (resulting in a com-
mon focusing plane for three light wavelengths), three are made of glass types with high anomalous partial color dispersion, while
two of the others have a high refractive index. The aspherical surface of the first lens in the rear group helps to reduce spherical
aberration and flatten the image field. While the optical construction in front of the aperture is a Gaussian type, the arrangement
of the lens elements behind it is similar to that in the Summilux-M 1:1.4/35 mm ASPH. This group comprises a „floating element“,
which is moved independently of the rest of the construction during focusing.
Summary: The Leica APO Summicron-M 1:2/50 mm ASPH. delivers exceptional picture quality and sets new standards in 35 mm
digital photography.
Optical design
Aspherical surface
Floating Element
LEICA APO-SUMMICRON-M 50 mm f/2 ASPH.
LEICA SUPER ELMAR-M 21mm f/3.4 ASPH.
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MTF-graphs
f/2.0
Aperture Stof/p25.8.6
[%]
[%]
100
100
80
60
40
20
0
1
80
60
40
20
0
0
3
6
9
12 15 18 21
Y'[mm]
0
3
6
9
12 15 18 21
Y' [mm]
f/5.6
[%]
100
80
60
40
20
0
The MTF is indicated at full aperture, at f/2,8 and f/5,6
at long taking distances (infinity). Shown is the contrast
in percentage for 5, 10, 20 and 40 lp/mm accross the
height of the 35 mm film format, for tangential (dotted
line) and sagittal (solid line) structures, in white light.
The 5 and 10 lp/mm will give an indication regarding
the contrast ratio for large object structures. The 20
and 40 lp/mm records the resolution of finer and finest
object structures.
tangential structures
sagittal structures
0
3
6
9
12 15 18 21
Y'[mm]
LEICA APO-SUMMICRON-M 50 mm f/2 ASPH.
LEICA SUPER ELMAR-M 21mm f/3.4 ASPH.
4
Distortion
Relative Distortion
Effective Distortion
[%]
5
Y'[mm]
12
4
3
2
1
9
6
3
0
0
-1
-2
-3
-4
-5
0
3
6
9
12 15 18 21
Y'[mm]
0
3
6
9
12 15 18
X'[mm]
Vignetting
[%]
Distortion is the deviation of the real image height (in
the picture) from the ideal image height. The relative
distortion is the percentage deviation. The ideal image
height results from the object height and the magnifica-
tion. The image height of 21.6 mm is the radial distance
between the edge and the middle of the image field for
the 24 mm x 36 mm format. The graph of the effective
distortion illustrates the appearance of straight horizon-
tal and vertical lines in the picture.
100
f/5.6
80
60
40
20
f/2.8
f/2.0
Vignetting is a continous decrease of the illumination to-
wards the edges of the image field. The graph shows the
percentage lost of illumination over the image height.
100% means no vignetting.
0
0
3
6
9
12 15 18 21
Y'[mm]
LEICA APO-SUMMICRON-M 50 mm f/2 ASPH.
LEICA SUPER ELMAR-M 21mm f/3.4 ASPH.
5
Depth of field table
Blende
Aperture Stop
Magnificationgn
Vergrößeru
2,0
2,8
4,0
5,6
8,0
11,0
16,0
0,7
0,8
1
0,690 - 0,710 0,686 - 0,714 0,681 - 0,721 0,673 - 0,729 0,662 - 0,743 0,649 - 0,760 0,629 - 0,792
0,787 - 0,814 0,782 - 0,819 0,774 - 0,828 0,764 - 0,840 0,750 - 0,858 0,733 - 0,882 0,706 - 0,926
0,979 - 1,023 0,971 - 1,032 0,958 - 1,046 0,943 - 1,065 0,920 - 1,096 0,894 - 1,137 0,853 - 1,214
1,169 - 1,233 1,157 - 1,247 1,139 - 1,268 1,117 - 1,297 1,085 - 1,345 1,047 - 1,409 0,991 - 1,531
1,450 - 1,554 1,432 - 1,575 1,404 - 1,610 1,370 - 1,659 1,321 - 1,739 1,264 - 1,850 1,181 - 2,071
1,910 - 2,099 1,878 - 2,139 1,830 - 2,205 1,771 - 2,300 1,688 - 2,459 1,595 - 2,693 1,462 - 3,203
2,799 - 3,233 2,729 - 3,332 2,627 - 3,499 2,503 - 3,749 2,338 - 4,201 2,161 - 4,950 1,919 - 7,055
4,458 - 5,694 4,280 - 6,016 4,032 - 6,591 3,743 - 7,556 3,381 - 9,690 3,017 - 15,01 2,560 - 185,1
1/11,3
1/13,2
1/17,1
1/21
1,2
1,5
2
1/26,8
1/36,5
1/55,8
1/94,5
1/∞
3
5
∞
40,20 -
∞
29,05 -
∞
20,36 -
∞
14,55 -
∞
10,20 -
∞
7,435 -
∞
5,128 -
∞
Aperture Stop 2,0
0.7
0.8
1
1.2
1.5
2
3
5
∞
0
1
2
3
4
5
6
Depth of Field [m]
AAppeertruturereSStotopp22,8.8
0.7
0.8
1
1.2
1.5
2
3
5
∞
0
1
2
3
4
5
6
Depth of Field [m]
LEICA SUPER ELMAR-M 21mm f/3.4 ASPH.
LEICA APO-SUMMICRON-M 50 mm f/2 ASPH.
6
Aperture Stop 4,0
B
0,7
0,8
1
1,2
1,5
2
3
5
∞
0
1
2
3
4
5
6
7
Depth of Field [m]
Aperture Stop 5,6
Blende 5,6
0,7
0,8
1
1,2
1,5
2
3
5
∞
0
1
2
3
4
5
6
7
8
Depth of Field [m]
Schäfeniefe [m]
LEICA APO-SUMMICRON-M 50 mm f/2 ASPH.
7
Aperture Stop 8,0
0,7
0,8
1
1,2
1,5
2
3
5
∞
0
1
2
3
4
5
6
7
8
9
10
Depth of Field [m]
crfnif
Aperture Stop 11,0
Blende 11,0
0,7
0,8
1
1,2
1,5
2
3
5
∞
0
1
2
3
4
5
6
7
8
9
10
Depth of Field [m]
Schärfentiefe [m]
LEICA APO-SUMMICRON-M 50 mm f/2 ASPH.
8
Aperture Stop 16,0
0,7
0,8
1
1,2
1,5
2
3
5
∞
0
1
2
3
4
5
6
7
8
9
10
Depth of Field [m]
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