While studying and researching about lighting principles, I have learned about one of the most important element to it–the contrast ratio. Contrast ratio is the difference between the subject’s main light or key light and its shadows. In post production this is best represented by the “Offset” or “Shadow” and “Gamma” or the “Midtone.” This ratio is critical to achieving the right mood for the scene. Easily put, subjects in a happy scene have very little or no shadow at all on them and dramatic scenes have heavy or really dark shadows on the subjects. To achieve this, the director of photography must be able to measure and control the varying light intensities being thrown upon the subject and this is where a light meter, like those of the Sekonic products, come in handy. Most of these meters measure light falling or being reflected on a subject and suggest the right settings for the camera to get the proper exposure. They are mainly used in Photography. Now, these things are really great but can be really expensive, too, especially for an indie filmmaker and a beginner like me, plus, what settings it suggests, in my opinion, would rather render useless to me when I use ND filters, which I often do to lessen the light coming into the lens while maintaining a desired depth-of-field. Anyway, I couldn’t afford one and I don’t think that one of those kinds is what I needed. All I wanted is something to measure light and I can do the rest when I get the next chance to shoot. Then I found this thing that they use in industrial lighting. They utilize this device to measure and make the proper lighting for buildings, warehouses, offices and other “interior design” stuff. I found it selling on eBay for merely $15. It is called “Digital Lux Meter.” It can measure minimal light coming from a dying candlelight or a burning match stick to the sunlight’s brightest at noontime. Perfect!
I have put it to the test when a friend filmmaker called me to shoot his low-budget full-length indie film with a Canon 5D Mark II, without the rigs, and, with, guess what–a couple of cheap hardware lights on improvised light stands! So I brought my homemade mattebox and right after our plane touched down, I sent somebody out to buy two more sets of those precious lights. So after I set up the lights, measured intensities with the lux meter and created the correct ratio for each shot, I simply check my camera display with the help of my buddy Histogram, adjust settings as needed and that’s it!
Not so bad, right? We have shot the entire film within eight days with the least of filming gears–not even a follow-focus and I couldn’t possibly have done it right without my beloved lux meter.
A few days ago, another friend asked me to shoot a few TV personalities endorsing a new product, (which I cannot show here), with his only available camera at the time–a well-used tape-format 3CCD Sony VX2100. Well, after the shoot, I think everyone have learned to appreciate that old camera more.
So whatever camera and lights you use, being able to measure light intensity to get the right light-and-shadow balance on your scene will definitely help you achieve the best results in any shooting situation.