Canon EF 50 mm f/ 1.2 L USM Lens 说明手册
Performance data:
Distagon
Distagon
®
T* 3.5/55
Cat. No. 10 49 59
1. MTF Diagrams
The image height u - calculated from the
image center - is entered in mm on the
horizontal axis of the graph. The
modulation transfer T (MTF = Modulation
Transfer Factor) is entered on the
vertical axis. Parameters of the graph
are the spatial frequencies R in cycles
(line pairs) per mm given at the top of
this page.
The lowest spatial frequency
corresponds to the upper pair of curves,
the highest spatial frequency to the lower
pair. Above each graph, the f-number k
is given for which the measurement was
made. "White" light means that the
measurement was made with a subject
illumination having the approximate
spectral distribution of daylight.
Unless otherwise indicated, the
performance data refer to large object
distances, for which normal
photographic lenses are primarily used.
The image height u - calculated from the
image center - is entered in mm on the
horizontal axis of the graph. The
modulation transfer T (MTF = Modulation
Transfer Factor) is entered on the
vertical axis. Parameters of the graph
are the spatial frequencies R in cycles
(line pairs) per mm given at the top of
this page.
The lowest spatial frequency
corresponds to the upper pair of curves,
the highest spatial frequency to the lower
pair. Above each graph, the f-number k
is given for which the measurement was
made. "White" light means that the
measurement was made with a subject
illumination having the approximate
spectral distribution of daylight.
Unless otherwise indicated, the
performance data refer to large object
distances, for which normal
photographic lenses are primarily used.
2. Relative illuminance
In this diagram the horizontal axis gives
the image height u in mm and the
vertical axis the relative illuminance E,
both for full aperture and a moderately
stopped-down lens. The values for E are
determined taking into account vignetting
and natural light decrease.
In this diagram the horizontal axis gives
the image height u in mm and the
vertical axis the relative illuminance E,
both for full aperture and a moderately
stopped-down lens. The values for E are
determined taking into account vignetting
and natural light decrease.
3. Distortion
Here again the image height u is entered
on the horizontal axis in mm. The
vertical axis gives the distortion V in % of
the relevant image height. A positive
value for V means that the actual image
point is further from the image center
than with perfectly distortion-free
imaging (pincushion distortion); a
negative V indicates barrel distortion.
Here again the image height u is entered
on the horizontal axis in mm. The
vertical axis gives the distortion V in % of
the relevant image height. A positive
value for V means that the actual image
point is further from the image center
than with perfectly distortion-free
imaging (pincushion distortion); a
negative V indicates barrel distortion.
Modulation transfer T as a function of image height u.
Slit orientation:
sag
White light. Spatial frequencies R = 10, 20 and 40 cycles/mm
tan
f-number
k = 3,5
f-number
k = 8
T (%)
T (%)
u (mm)
u (mm)
0
20
40
60
80
100
0
5
10
15
20
25
30
35
0
20
40
60
80
100
0
5
10
15
20
25
30
35
Relative illuminance
E (%)
u (mm)
0
20
40
60
80
100
0
5
10
15
20
25
30
35
k = 3,5
k = 8
Distortion in % of image height u
V
u (mm)
-2,0
-1,0
0,0
1,0
2,0
0
5
10
15
20
25
30
35
Subject to change.
Printed in Germany 29.05.2002
Carl Zeiss
Camera Lens Division
73446 Oberkochen
Germany
Telephone ++49-7364-20-6175
Fax ++49-7364-20-4045
eMail: photo@zeiss.de
http://www.zeiss.de/photo
Camera Lens Division
73446 Oberkochen
Germany
Telephone ++49-7364-20-6175
Fax ++49-7364-20-4045
eMail: photo@zeiss.de
http://www.zeiss.de/photo