if you want to have more control of your lighting in exterior shots, and can't afford the equipment, simply rig mirrors and harness the daytime sunlight. the mirrors can be constructed cheap (cardboard, aluminum foil) and positioned on music stands. using these mirrors you can direct the sunlight into your shot to wherever you want the focus of your light. try and film in a place that isnt completely being beared down upon by the sunlight, that way it doesnt wash out the lighting in your shot. you can use white sheets propped infront of your mirrors to soften the light, or double up your mirrors for a harder lighting.

You can use bounce-board to reflect light onto your subject or alternately to shade your subject and/or camera. Depending upon your camera you can also adjust the white-balance and contrast as well as how much light gets in. A lot of this stuff with the camera is trial and error you should do before the day you intend to shoot so you have a chance to see not only what it looks like on the little monitor but later when dumped onto a computer.

You will also find that most computer editing programs can pull out a miracle or two in adjusting lighting. I had scenes that were a bit overlit that I didn't realize at the time and which I feared might be ruined. Adjusting contrast in Final Cut Pro allowed me to fix them right up.

Having said that its better to get it right the first time and not depend upon editing programs.

RJSchwarz
San Diego, CA