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Aberrations |
No lens system is 100% perfect, aberrations are optical imperfections in the produced image which are caused by the lens set-up itself. These can either be distortion of images or the creation of coloured fringes to edge of an image. |
Aerial image |
An aerial image is an image which is formed within an optical lens system,
it appears to 'float' when viewed with the naked eye and is formed by
the projection of the film image into the condenser lens. The condenser
lens makes the diverging projector image converge thus providing a focused
subject image for the digital video camera. |
Claw |
The claw (or claws) of the film projector are the small projecting devices
located near the gate which pull down the film frame by frame to allow
the projection of the single stationary images. |
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Condenser lens |
A condenser lens is a lens which collects light and redistributes it
for the purpose of illumination. In this case, the condenser lens focuses
the projected image to provide the subject for the digital video camera. In this case,
a plano-convex lens is needed (i.e. one with a single flat surface and another convex surface). |
Diffused light source |
Diffused light is light which has been scattered by reflection and refraction.
In this case, the diffused light source is a soft light with no discernable
centre to its density. This is achieved by using the opal diffuser to
scatter the light beam from the new halogen lamp. |
Film chain |
A film chain set up is essential a projector, focusing lens set-up and
a digital camera to capture the film images. Film chain set-ups can
be simple affairs shooting projected film in real time through to elaborate
single frame capture systems. |
Film scanning |
Film scanning is a process where each individual frame is scanned one
at a time in a similar manner to how paper or transparency images are
scanned by commercial scanners. |
First surface mirror |
A mirror with the reflective layer on the outer surface, used to avoid
ghost images from additional reflections if light has to first pass
through the mirror glass and then hit the reflective layer, provides
for higher quality images. |
Frame streaking |
Occurs when frames are grabbed when not stationary. Streaking will occur
within the still image caused by the film frame moving during the capture
period. This is characterised by vertical streaks of lighter areas of
the image. |
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Gate |
The gate is the aperture over which the film passes. Illumination from
the light source passes through the gate assembly, with the film in
between before being focused by the lens for projection. The gate width
(and height) defines how much of the film frame can be projected. |
Hot spot |
The hot spot is a portion of the viewed image where it appears to be
brighter than the surrounding areas. This is eliminated by the use of
a diffused light source to scatter the light beam emerging from the
light source. |
Mouse-down |
Is the event which occurs when a mouse button is pressed i.e. closes
a switch contact which passes an instruction to the computer. |
Opal diffuser glass |
An opal diffuser glass is a white opal piece of glass which has very
high light scattering characteristics and as such is very wasteful of
light energy. Produces a near perfectly uniform light source when placed
in front of a light source. |
Professional telecine |
Professional telecine systems use a variety of high technology solutions
based on CRT (cathode ray tube) or CCD (charged coupled device) technologies
to convert film frames into video footage, usually in real time. These
sophisticated systems allow for on the hoof changes to exposure and
coloration. |
Take up reel |
The take up reel is the rear spool on the projector which takes up the
projected film and winds it automatically. |
Under scan |
Under scan occurs when a domestic TV monitor (or other dispaly device)
does not display the whole of the received image. Each TV monitor varies
in the amount of image (from all sides) that is effectively cropped. |
White Balance |
White balance is the white light level that a camera assumes to be neutral.
This can vary depending upon light source (tungsten lamp verses daylight
for example) or other factors. The white balance can be set against
any white light source (a bulb, white sheet of paper etc.), in this case,
we assume the diffused white light source to be neutral. |
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