JVC Professional APRIL 2007 NAB-2007 The ProHD Report
Copyright 2007 JVC Professional Products Company All rights reserved Page 40 of 43
Using a 2/3-inch lens (with a native min focal length of 5mm) with the 1/3-inch
adaptor increases the focal length by a factor of 1.97 to 10mm, producing a
horizontal angle of view of approx. 27 degrees, which may not be wide enough for
HD ENG.
Fig. 22. This diagram shows that the Horizontal Angle of View is
reduced when using ½-inch and 2/3-inch lenses with adapter to fit 1/3-
inch camcorder given the same minimum focal length (in this case
5mm). Therefore, existing inventory of wide angle (½-inch and 2/3-inch)
SD lenses are of particular interest to try to work with the ProHD
camcorder, particularly lenses with 4mm or lower minimum focal
length, and lenses with wide angle converters.
The bottom line using SD lenses in ProHD camcorders? If you have ½-inch
and/or 2/3-inch SD lenses already in your inventory, then you owe it to yourself to
try them out on your HD250U. The US list price for the HD250U without any lens is
$9,995 and only $1,000 more ($10,995) with the standard professional Fujinon HD
16x lens. Depending upon your SD lens inventory (1/2-inch or 2/3-inch), add the ½-
inch (JVC ACM-12) or 2/3-inch (JVC ACM-17) lens adapter for about $750. Shoot
the same ENG test footage with the standard HD and the existing inventory SD lens,
view the material (preferably) on a studio monitor with full native HD pixel
resolution (JVC offers two suitable models of flat panel studio monitors) or on a JVC
rear projection D-ILA HDTV, and then make your decision based on your specific
situation. The wide angle models are likely to work better and be more suitable than
the longer focal length models. You may perhaps decide that your HD ENG efforts
may be sufficiently served for an initial period of time using some of the existing
inventory SD lenses, limiting your initial investment. In the longer term, real HD
lenses are required to provide optimum image quality and acquisition flexibility.
Lens adaptereffect onHorizontalAngle of View
5mm
–
1/3-inch lens
–
52 de
g
rees
–
no ada
p
te
r
5mm – 2/3-inch lens
1/3-adapter – 27 degrees
5mm – 1/2-inch lens
1/3-adapter – 37 degrees