Light meters may seem like relics of a different era, but they are still consistently used by filmmakers working with digital cameras. We've shared a fantastic guide about using light meters from Ryan E. Walters before, and now we've got a great post on why light meters are still relevant and how they can help you light and expose your shot, and get a far more precise image overall.
This is a guest post by Cinematographer Ryan E. Walters.
With the proliferation of digital cinema cameras these days, I often get asked, "Do you really need to use a light meter? After all, isn't the whole point of working with digital 'What You See, Is What You Get?'" While a case can be made for that perspective, I believe that by doing so you miss out on the power, efficiencies, and knowledge that working with a meter adds to your skill set. Here is why I think the light meter is a critical tool to use with digital cinema cameras.
Using A Meter Gives You Power
Precisely control the look of your images: Great lighting doesn't just happen by accident, or by blasting light everywhere on set and recording it. Great lighting happens through control and precision. If you want your images to stand out from the crowd, I would suggest that you need to be purposeful and intentional with your lighting. That means you need to know how your camera responds to light, and then you need to precisely place those values where you want them in the frame through careful lighting. The only way to know precisely where those values fall is through the use of a meter. A waveform or histogram can give you a good overview of a scene, but it can't tell you that you need 10 more foot candles of light, or that you need a half stop less of light to get to where you want to be. It only tells you that you need more or less light.
Ability to match shots or scenes shot at separate times or at different locations: If you know what your light levels are for a given scene, then you can come back and shoot pickup shots for that scene weeks or months later and they will intercut perfectly. (Even if you end up using different lighting instruments then what you initially shot with). Furthermore, by knowing the light levels of the initial scene you can make a completely different location match the original location through lighting and creative camera work. I have worked on several projects where I have had to keep a consistent look throughout the project, but the scenes were shot over many months in different locations, and yet the end result looked and felt like it was all shot in the same place, using the same location. (This is especially helpful for interviews for documentaries). If I didn't have my meter and didn't know the light levels for each shot the look would have been inconsistent.
Know if a specific look will hold up: Today's digital cameras offer a lot of flexibility in the looks that they create both in camera, and then later through the final grade. If the time is taken during preproduction to test various looks, you can transfer the information you learn in prep to your meter. Then by taking readings on set you will have an accurate way to know for sure if the details in that black car will hold up after the shot has gone through the final grade. Having the power to know this in advance is a lot more affordable than having to reshoot something, or take the final look in a completely different direction because it didn't hold up.
Using A Meter Makes You Efficient
Makes you faster on set: It seems like these days there is a continual push to work faster and get more done in a day. So I am always looking for tools that allow me to be more efficient as well as allow me to deliver the quality imagery I desire. My meter does just that. By using a light meter, I can take measurements and know exactly what changes need to happen instead of guessing. It also gives me a clear, precise means of communication. I can tell my Gaffer I need 23 foot candles of light at this location, or I can say I need a double scrim in that light over there. During preproduction, I can also talk with my Gaffer and say: I want my key to be at T4 @ ISO 800 and 24 fps, my fill at T1.4, and my kicker to be at T8. Or I can say I want a key to fill ratio of 8:1. And then she can make informed suggestions on the type of lighting units we should use to get my desired results. This a lot faster than just saying, "I need more or less light here," and then making several adjustments to get to the correct levels.
Ability to light multiple locations at the same time, or pre-light the day before: Lugging a camera system around with you to light your locations not only adds extra work, but it can also incur additional expense and time that can easily be avoided. By knowing how your camera system responds to light, you can use your light meter to light a secondary set while you are shooting on the first set. Or you can be lighting the set the day before to make the shoot day go smoother and quicker. I have worked on productions where we had to shoot in 4 locations in one day and we did not have the budget to rent 4 different camera systems. We also did not have the time to transfer the camera back and forth to preview the scene, nor was there the budget to add an extra days camera rental for the pre-light day. By knowing how the camera system responds to light, I was able to have each set lit and ready to go before the camera arrived, allowing us to make our day, and keep the budget reasonable.
Post production is easier, quicker, and more affordable: By maintaining consistent light levels within a scene it means that when it comes time to grade the footage less tweaking and shot matching has to be done in-between individual shots. This speeds up the grading session, and it allows for more time to finesse/grade the footage rather than correct/balance it. And, consequently, it also reduces the post production costs. I have also worked on productions where the turnaround was so tight that there wasn't time to do any grading, or correction. The end deliverable was a straight edit of the footage. Because I had controlled the light levels and maintained a consistent look shot to shot, post production was a breeze and no one ever knew that the footage was not color corrected or graded.
Using A Meter Gives You Knowledge
How a camera responds to light: The one consistent with digital cinema cameras these days is that they all place mid-tone at different values. Depending on the camera system and the recording format, mid-tone can fall anywhere from 38% IRE up to 55% IRE. These are huge differences in placement, and you may or may not like where that placement falls. By using your meter and testing your camera system, you can get an accurate representation of how that camera responds to light. And then, if you use a program like the DTS software, you can map the camera response to the meter. (Examples of different mid-tone values can be seen in the Best Practices section HERE).
Able to scout a location and know what you need in terms of light levels: By carrying your meter with you on a location scout, you can measure the light levels and know exactly what it will take to get your exposure to the levels you need, and what challenges the location presents. Knowing this information beforehand will enable you to be better prepared going into the shoot, and save you a lot of time and headache on set.
Trains your eye to judge light levels: The more you work with a light meter, the more you can train your eye to get a better sense of what different light levels and lighting ratios look like. As you train your eye to see these levels, you will also gain the knowledge of what the lighting requirements are to get there. Over time, as you train your eye you will be able to light faster, and make more informed lighting choices. At some point, you may even become skilled enough to light completely by eye and not even need a meter. You will just walk into a location and know that what you need is a Tweenie bounced into a 4x4 card from camera left about 4 feet away from the talents position. :)
For me, the point of using a meter in the digital age is to take my lighting skills and knowledge to the next level. Lighting off of the monitor, via the histogram or waveform, does not offer me the same power, efficiencies, or knowledge that I get from using a meter. You can light using those other tools, and many people take this approach. But for my style of working, those tools do not offer the same benefits that my meter gives me.
If you want to learn more about how to use a light meter or how to profile a camera, check out my Sekonic Page. I also have a Review of the 478D, as well as information on the Urban Legend of 18% Grey.
What are your thoughts? Do you see the light meter as a helpful tool or as an antiquated piece of kit better suited for film? How do you prefer to light a set and set your exposure?
This post originally appeared on Ryan’s Blog.
Ryan E. Walters is an award-winning Oregon-based cinematographer. His work has allowed him the opportunity to travel worldwide in the pursuit of telling stories that are visually compelling. His experience includes feature films, documentaries, commercials, and shooting for Comcast, TLC, Oxygen, and the Discovery Channel.