Filters for special effects

Filters - what for? I can hear someone say, or "I never use them!” This may sound very elementary, so at the risk of trying to teach Granny to suck eggs, I’m going to say something about filters. I have to admit though that I have often found myself without the one I need for a particular purpose, there being so many!

The thing is to decide first if you want to bother with them, for the electronics can take care of the most obvious use: that is, the correct white light balance. Most cameras have back lighting compensation, even though it may be a bit hit and miss with a basic camera.

I find a polarising filter one of the most effective. It can be used to take out unwanted reflections in water or glass by rotating it until you get the best result. It can work wonders with skies and make a very dramatic scene. Note that the light from a blue sky is most polarized at right angles to the Sun and so in this
 
 
 
 

direction you can produce a dramatic contrast between the blue of the sky and any puffy white clouds.

There are many colours and several shades from light to quite dark. Many are graduated to obtain a useful effect. Using a very light neutral graduated filter, I find can be effective if used on the top half of a landscape to take the glare out of the sky where necessary.

It is interesting to try out various filters to experiment with such effects as sepia, to create a ‘ye olde worlde’ look!

To achieve Day for Night with video is more difficult than with film, as the electronics in the camera take over the exposure control and interfere with creativeness! Where with film, to shoot a moonlight scene for instance, the choice of filter would be a blue combined with under exposure, and would be best shot in strong sunlight under blue skies. Low angled slightly
 
 
   
 

back-cross lighting being essential to make dark shadows. With video, unless yours is a more sophisticated camera, you may have to use two filters for a moonlight scene; a blue combined with a darkish neutral density to make a contrasty dark bluish effect, with little or no shadow detail. (It would need experimentation.)

An old trick used in cinematography for soft focusing was to stretch fine gauze at the front of the lens, but I have not tried this with video. It would be worth experimenting.

We all know about the various star filters, I think they have a place, but again, should be used with discretion!

There are so many effects possible that it would be too much to write about here, I think filters are well worth experimenting with to achieve the required effect although it is obvious that all this can be achieved in the computer after shooting.

by Jon Woolmer