I'm changing gear today, literally and blogging about lighting for filming, it can and does relate to stills too. Here's the scenario: You have several pages of dialog to shoot, involving more than four actors, all with dialog. The scene needs a master establisher wide shot, several two and three shots, a tracking shot and possibly eight singles. Script time of day is 11am. This scene is going to take you all day. You arrive on set at 6am ready to shoot at 8am. It's going to be a sunny day according to the forecast. The location (interior of an orangery) is facing west.
You are the director of photography or simply the photographer, what is your lighting plan? There are two significant things to consider here; the ambient light and the temperature of the light you want. Although the scene will consume about five minutes of screen time it's going to to take all day to shoot, so your main consideration is the continuity of the light. You need daylight for the entire scene, and as it only takes up five minutes of screen time,it's going to take the best part of 9 hours to shoot. Therefore the sun that is at 8am over the other side of the building, will by 3pm be blasting it's beams right through your windows. As you can see from my picture, you have to cheat for sun, as light that you have control over all day long. By using the white silks you defuse the light enough so as not to create shadows, so the light is daylight, constant and directional without being contrasty, with the lights being at a constant angle. Should you need to return to this scene but later in the afternoon, say a script time of 5pm, you might want to lower your lights and add a 1/4 cto (colour temperature orange) to the lights just to give that late afternoon warmth, the same would apply to early morning but here you might want to use a gel which is described as 'straw", a thinner warmth you find with morning light. As photographers, we don't often have the luxury of big expensive HMI lights and generator trucks, but the principle can be used with less elaborate lighting rigs. In stills photography we should take some tips from the cinema world and use the colour, intensity and direction of lighting to give our pictures the feel to compliment the subject. By using gels on either constant light sources or flash we have a lot of control over light temperature, something that saves us time and trouble when we try and emulate this on the computer.