Video Doors for the Arri IIC
There are three types of Arri IIC video doors. One is a beam splitter that replaces
the light trap in the door. The second is straight through that replaces the
optics in the door and a third "looks" directly into the eyepiece. I have made
and used all three types. I prefer the straight through door for rigging. It
is smaller and lighter than most beam splitter units.
To make a straight through door you need extra II C camera door without optics
because you need a regular door with optics to align and focus the shot. The
detail that you can see on a video assist is not good enough for focus or seeing
fine detail in the shot. If you have more than one camera you might modify one
door and use it for rigging. You can put the Arri optics back in a modified
door, but it takes more time than you might want to spend in the field. An Arri
II A or II B door can be modified to work as a finder on a Arri II C, but will
leak light unless very carefully taped or modified with extra metal or epoxy
to fit the Arri II C tightly. I haven't checked if a Cineflex door could be
made to fit as a finder door. The cameras are almost worthless otherwise.
You need a 25 mm lens with an iris and a maximum outside diameter of 1" or less.
Less diameter helps for alignment of camera. I have found the older lenses made
for 16 mm "C" mount cameras quite work well. A 25 mm (1 in.) lens works well
with about a .200" extension tube. Some extension tubes can be turned down to
length. Some video cameras have flange to film adjustments. Some lenses can
be turned down smaller than 1" to fit the tube. Some 8-mm lenses will cover
the format. Many older 16 mm lenses are slower, f 2.5, but are usable because
we are looking at all of the light on the ground glass. There is no beam splitter
to reduce the light to the video camera.
Access to the F stop on the video camera lens is necessary for a good picture
under different lighting conditions and for different film speeds. I have cut
holes in the side of the Arri II C door for this purpose. It's not "Professional"
looking, but it works just fine. Tape over the hole to avoid light leaks.
Any beam splitter has an internal loss that absorbs part of the light and a
faster lens will be needed. Some older "C" lens mounts with lots of thread can
be spaced out with a spacer turned on a lathe from brass or aluminum to focus
I have used 3 different Sony CCD models with success. I found differences in
the electronics that effect the camera's ability to handle various light levels
without a stop change.
These design works with most of the smaller CCD cameras out there. The size
of the camera must be considered for clearance of the camera body. Some cameras
require regulated voltage.
Many cameras have fragile power plugs that can be replaced with 4 pin Cannon
plugs. On some you can add a side mount 4-pin plug on the case that is wired
to the supplied cable. Check polarity.
The third method is to view the image through the regular eyepiece. There are
some commercially build ones out today. Bracketry is difficult to align the
camera with the eyepiece.
© Copyright 1999-2004 Ron Dexter. All Rights Reserved.