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Technical Reference
Distortion
MTF (Modulation Transfer Function)
●
Distortion is an aberration where the geometric fi gure of the
object is not reproduced faithfully at the image plane. It is
normally represented by the level shift of an image point from
its ideal position by a percentage of image height or width.
●
MTF (Modulation Transfer Function) represents the declining
contrast rate when shooting a chart consisted of black and
white lines.
HD Lens
Three-CCD lenses
Day & Night Lens
The day & night lens uses an advanced optical
design, special optical glass, and other state-
of-the-art technologies to focus light (visible to
near-infrared 400- 1000 nm) on the same plane
to prevent the focus to become blurry enabling
sharp images.
Object
Lens
Barrel distortion
Pin-cushion
distortion
MTF %
0
20
40
60
80
100
Low <- Number of TV lines -> High
●
Based on design techniques accumulated through our
experience in production of broadcast lenses, high resolution,
small and light-weight HD lenses with minimal aberrations
have been realized.
The chart at the right shows the difference between an HD
lens and a conventional CCTV lens.
As the number of TV lines increases, the disparity in MTF
becomes greater.
●
Three-CCD cameras have thicker glass between the lens and
the CCDs than that of single CCD cameras because they
use three CCDs to correspond with the red, blue and green
colors separated by a prism.
Fujifi lm's three-CCD lenses are designed to optimally match
three-CCD cameras. The chart shown at the right explains
the difference in MTF when a three-CCD lens or a single
CCD lens is mounted on a three-CCD camera.
0
20
40
60
80
100
MTF (%)
Three-CCD lens
Single CCD lens
Center
Diagonal
Image height
0
0
50
100
150
200
10
20
30
40
50
60
70
80
90
100
MTF (%)
HD lens
Conventional lens
Spatial frequency
A standard lens (for visible light)
is mounted on a day & night camera,
and used under near-infrared light.
A day & night lens
is mounted on a day & night camera,
and used under near-infrared light.
Result: Blurry image
Result: Clear image without getting blurry
Visible light
focusing plane
Near-infrared light
Near-infrared light
Visible light
Visible light
Near-infrared light
focusing plane
Focusing plane
Zoom
Vari-Focal
HD Fish-Eye
HD
F
ix
ed
Fo
ca
l
HD Vari-Focal
Technical Information
