Special effects is a vast topic and really outside the scope of these pages. However, it is an exciting area with huge potential for the low budget filmmaker, so we thought we should mention a few starting points.
We usually think of special effects as being created 'using computers' or 'in post production', but a number of exciting things can be done 'in camera'. Carefully planned speed changes or reverse footage can provide quirky effects; as can puppetry or animation mixed into a live action film. They have stood the test of time - so don't rule them out. A few examples to get you thinking:
an object lying on the floor magically snaps up into the palm of a hand
an empty room : fast cut to - same room, same lighting a huge puff of smoke : fast dissolve through to - someone has appeared in the room.
a hat mysteriously floats off someone's head, a chair slides over and blocks a door
a computer mouse moves of its own accord; the computer screen turns and looks at someone.
Locked off' cameras (ie cameras firmly fixed on tripods) are essential for most effects shots
Two examples of chromakeying:
Film children dressed in appropriate costumes against a keying background talking about a particular place. In the edit, key out the background and put the children against a still image of the place they are talking about.
Film someone acting like they are driving a fast car against a keying background. Take film from a moving car, speed it up and put the two together.
Compositing is putting together different layers of film to create a desired effect. Once you understand the basics it can help you create great effects quite simply. You create different sequences of film, usually in precisely the same place, at the same time, with a locked off camera. And then use masks or mattes in the edit suite to hide or reveal elements of your image.
Again, this is best explained with examples:
Character walks across screen, but disappears as she passes a certain point.
How? - Film someone walking across the room, and then film an equal length of the same shot with nothing happening. In post, split the screen in half and make one side of the screen the action of the character walking, and the other side the empty room.
One of the simplest things you can do is place new cutout elements in the foreground, literally cutting out a still image and laying it over your moving action.
Example: In cutout animation, you want your characters to appear trapped behind bars. In the old days you had to lift the cage off and place it back down for every single frame. Now you put the cage in afterwards - so the animation of the trapped figures can happen easily without the bars getting in the way.
In advanced programs, this can often be a layer with no background created in Photoshop
You have a perfectly composed shot but the hands of the puppeteer keep getting into the shot : find a frame at the start or the end where there is no movement : and use this still to mask over where the hands appear.
Successful effects take planning - allow a lot of extra time, but don't be put off
Nowhere has the desktop computer revolution cut costs more dramatically than in sfx - what could have cost you £2000 a day to do in Soho in 1985, can now be done at exactly the same quality on a £600 home computer with say Adobe After Effects