I'm trying to see the color in the opal that I see live through the
camera's eye. The color in the opal is astonishing, georgeous but I
can't get it in the camera.
Opal consist of tiny silica spheres held together. The play of light
is due to splitting of light beam by spaces between the spheres.
Laws of Optics dictate that Angle of Incidence equal to Angle of
Reflection. That means that in order to see the opal play of color,
camera must be positioned along the Angle of Reflection. That is the
In practice if we do that, the picture that we get is not what we
see. If our cameras would be transparent we can position light
directly behind the camera, but cameras are not transparent and that
would not work.
The solution is to use a “beam splitter”. I will try to describe it,
but without use of drawings it is confusing, so Google on it for more
Make a cardboard tube. Inside walls must covered with light
absorbing material like black velvet.
In the center of the tube position glass plate at exactly 45 degrees
angle to the tube’s long axis.
In the side of the tube make an opening in such a way that a light
beam through the opening would strike the glass plate in the center.
Position tube between camera and opal aligned with the direction
camera is facing.
Shine strong light through the side opening at 90 degrees angle to
the long axis of the tube. Take a picture.
The mechanics as following:
Light beam through the opening strike the glass plate. Depending on
glass refractive index, some of the light will go through, but some
will be reflected towards opal. When light strike the opal, a portion
will be reflected towards the camera alongside the tube axis. When it
hit the glass plate, again some of the light will go through, and
some will be reflected. What it means that only a small portion of
the light will reach the camera, so exposure must be long, and you
would need sturdy, professional quality tripod, but picture should
approximate what the eye sees.
Beam splitter can be bough ready made, if money is not a problem.