1 The Director of Photography – an overview

132 Practical Cinematography
effect remains more or less the same at all the focal lengths of the
zoom, whereas in front of prime lenses the effect is different on differing
focal lengths. This is mainly due to the variation in the amount of
physical net in the optical path. I cannot recommend this trick for
16 mm, as the diffusion created, even with the finest net, destroys the
definition of the image far more than is usually acceptable.
Be very careful that the net put in front of the lens does not become
sharp enough to give you a pattern on the scene. This is a particular
problem with 16 mm and short-focal-length lenses. It will become
immediately apparent the moment you move the camera.
Nets will lend their own colour to a scene – a brown net will add an
overall warmth and richness to the tones, for instance, the darker nets
adding more to the shadows and the lighter nets to the highlights. Nets
will also give a slight star effect to point sources. A candle flame shot
with a black net can look very attractive and ‘Christmassy’.
Matching shots
You need to be very careful when using different focal length lenses
during a scene on which you are using diffusion filters. Longer focal
lengths will usually need less diffusion than shorter lengths. Fortunately,
these things are fairly WYSIWYG (what you see is what you get), but
you have to look through with the stop on – it makes a difference.
Enhancing filters
These are very unusual filters that bring out, or accentuate, just one
colour without affecting any of the others. They come in all the primary
colours, though red is for some reason the most used. Both Tiffen
and Hoya produce excellent enhancement filters. If you are to photograph
a commercial with a red car as the product, do not leave home
without a red enhancer – it will bring the car forward a treat.
Fluorescent light correction
The FLB filter corrects fluorescent light to type B film, i.e. tungstenbalanced,
and FLD corrects fluorescent light to daylight film. With
modern negative emulsions they are hardly necessary for cinematography,
as the tubes are so much better these days and the processing
laboratories have so much more experience in printing scenes shot
under this lighting. Remember that if you can light all the set with fluorescent
light the laboratory correction will be most successful. Mixed
light is a nightmare.
Polar screens
Polar screens are used to darken the blue portion of a sky in colour
photography as well as reducing unwanted reflections in particular
parts of a scene. The classic use is to make the colour of a car more
solid by reducing unwanted glare in the paintwork.