Canon EF 90-300 mm f/ 4.5-5.6 Lens 部件
Performance data:
Tele-Apotessar
Tele-Apotessar
®
T
* f/2.8 - 300 mm
Cat. No. 10 45 33
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.