F-Number
2/3
” Lens
KJ
20x8.5
B LO
32
BMT
Zoom Ratio:
20
x
Wide Focal Length:
8.5mm
F-Stop: F
1.8
1/2” HD
Lens
KH
20x6.4
Zoom Ratio:
20
x
Wide Focal Length:
6.4mm
F-Stop: F
1.4
2/3
” HD Lens
KJ
20x8.5
B with LO-
32
BMT
Zoom Ratio:
20
x
Wide Focal Length:
8.5mm
F-Stop: F
1.8
1/2”
Lens
Since neither the focal length nor the effective aperture has changed, the F-number remains the same,
F
1.8
. Thus, there is no optical sensitivity “loss” involved when using a
2/3
” native lens with the LO-
32
BMT
on a
1/2
” camera. As a comparison, if instead of using the
2/3
” KJ
20
x
8.5
B lens and LO-
32
BMT adapter,
you were to substitute a
1/2
” KH
20x6.4
HDTV lens, the adapter would no long be necessary. By applying
the same formula, F-Number = f/D, to the
1/2
” KH
20
x
6.4
lens, the lens will have a faster F-Number, F
1.4
,
compared to the
2/3
” lens and LO-
32
BMT combination.
Focal Length
When using a
2/3
” lens with a LO-
32
BMT adapter mounted to a
1/2
” camera, the actual focal length
of the lens does not change. However, the angle of view associated with that focal length changes.
In this case, the lens will visually be more telephoto, by a factor of
1.38
x. As an example, the
2/3
”
KJ
20
x
8.5
B HDTV lens (
58.9
0
angle of view at
8.5
mm when mounted on a
2/3
” camera) will visually
appear to have a
44.6
0
angle of view, that equates to an equivalent focal length of
11.7
mm
(
8.5
mm x
1.38
=
11.7
mm)
The actual F-Number of a lens does not change when mounted on a different format size camera.
Using the
2/3
” KJ
20
x
8.5
B HDTV lens as an example, its maximum aperture is F
1.8
. When that lens is
mounted on the
1/2
” camera with the LO-
32
BMT adapter, the focal length and effective aperture of
the lens do not change.
The
Canon LO-
32
BMT
adapter allows you to mount a
2/3
” B
4
bayonet lens onto
any Sony
1/2
” proprietary mount camera such as the new XDCAM HD series,
PDW-F
330/F350
while not affecting the optical quality of the lens. It is important to consider
the following information when using a
2/3
” lens with a LO-
32
BMT adapter mounted to a
1/2
” camera.
2/3
” HD Lens
KJ
20x8.5
B Focal Length
at Wide Angle
8.5mm
2/3” HD C
amera
Angle of View
58.9
0
1/2” HD C
amera
Angle of View
with LO-
32
BMT
44.6
0
Visual Equivalent
Angle of View
in
2/3”
11.7mm
The formula for deriving the F-Number of any lens is as follows:
F-Number = f / D
f = Focal Length D = Effective Aperture
Canon’s
New HDgc Lenses
for Sony’s XDCAM HD
Canon USA Inc.
Broadcast and Communications Division
65
Challenger Road, Ridgefield Park, NJ
07660
1-201-807-3300
/
1-800-321-4388
www.canonbroadcast.com
1.
The images produced will appear visually more telephoto by a factor of
1.38
x.
2.
The actual F-Number of a lens does not change when mounted on a different format size camera.
If the lens is F
1.9
in the
2/3
” format, the lens is also F
1.9
in the
1/2
” format.
3.
The Focal Length and F-Stop markings on the
2/3
” lens are correct in either format.
4.
It is highly recommended that HDTV lenses always be employed on HDTV cameras.
The
Canon LO-
32
BMT
The
2/3
” KJ
20
x
8.5B
lens
with LO-
32
BMT as compared
to the
1/2
” KH
20x6.4
lens.
2/3” HD C
amera Angle of View
58.9
0
1/2” HD C
amera Angle of View
with LO-
32
BMT
44.6
0
Specifications subject to change without notice. Errors and omissions excepted.
Weight and dimensions are approximate.
CNB3000-00609-78
©
2006
Canon U.S.A., Inc. All rights reserved. Canon is a registered trademark of Canon Inc. in the United States
and may also be a registered trademark or trademark in other countries. IMAGEANYWARE is a trademark of Canon.
