Shooting Theatrical Productions: Contending with challenging lighting

by Andrew Alexander
Published on Aug 26, 2002 12:00 AM



Camcorders like lots of light to work, so first off all, in low-light everything will generally look grainy and dark. In your average situation, the autofocus will hunt around, trying to find a sharp edge to focus on in the gloom. When the lights come up, say to put a spotlight on a major character, the focus will find a point to lock on - finally - but the autoexposure will try to equalize the light levels to a point where everything will look extremely bright. The actor you're focusing on suddenly looks like a white ghost. Now the lights go down again, the autoexposure tries to compensate by boosting the gain and everything gets grainy, and the autofocus goes nuts trying to find an edge... all in all, a pretty unpleasant product.

Never fear, there are ways around this, and it’s all about learning how to master your manual focus and manual exposure options.

Focus

Manual focus is now your best friend. If you can manage it, set the manual focus before the production starts and focus in on a specific point where the action will be. Knowing where the talent is going to spend the majority of their time on stage helps here. Simply get someone (or something) on the stage, zoom in as close as you can (optically - digital zoom will just degrade the image, so turn it off or don’t use it if you can), and let the camera focus. Now turn off the autofocus and zoom back. You’re all set. If the talent wanders out of the area of focus, you can either adjust it manually to get it right, or if there is enough light, turn on the autofocus just long enough to get the proper focus, and turn it off again. Don't do this if there isn't enough light - the autofocus will hunt around and mess up your image.

Exposure

You have three options available to help you deal with radical lighting levels on the stage. The first, and most widely available, is manual exposure control. This control lets you adjust how bright the image will be when it's recorded. For photography enthusiasts, this control is similar to aperture control, where you control the amount of light hitting the film. Auto exposure works by the camcorder trying to match the average light level it's receiving to a predefined target value, but since you will be dealing with areas of very bright and very dark lighting, the autoexposure will tend to either over- or under-expose everything. Again, turning on the manual exposure setting here will save you. You will want to turn it down to the point where you can't see any "grain" in the dark areas of the image, or more importantly, where your talent is not a big white ghost. With high levels of lighting on the stage, this will be a disturbingly low value. Throughout the recording process, you may need to adjust this value as the lighting conditions change. Too dark, and you won't see anything; too bright, and you'll see white ghosts where the talent should be. You might get lucky and find a sweet spot where things are acceptably dark and bright, and not change it at all. This is the best case scenario.

The next other possibility is manual shutter control. In cases of extremely low light, you may need to lower the shutter speed. Not all camcorders can do this; typically, a consumer camcorder has its shutter speed default to a speed of 1/60th or 1/100th of a second, and manual shutter speed will let you increase this value, not decrease. Setting your camcorder to 1/30 shutter speed will give you a substantial increase of light without really affecting the look of the recorded image. Setting the shutter speed to 1/15 will increase the light level further, but will make the recorded images look "strobic". If you can go as low as 1/8, you will have a dramatic amount of light, but your images will be very blurred and extremely strobic. Most camcorders with a "low-light" mode shoot at 1/15 shutter speed.

The last option is for some camcorders which have a "gain control" - this is similar to manual exposure control. Gain control allows you to artificially (i.e., digitally) boost the amount of light captured by the camcorder. The problem here is that if you have a lot of grain in the image because there's just not enough light, then while the image will be brighter with increased gain, so will the grain. It's like hearing a radio with a lot of static. To try and understand what you're hearing, you might turn up the volume. The program gets louder, but so does the static.

Next week, we'll look at different styles of recording the production - from the documentary style to multiple-camera recordings.