A cinematographer has many exposure tools to help him or her. These are the top six, each one giving more information than the last.
Watch the video:
What makes cinematographic exposure different from photography?
Cinematography has unique challenges compared to photography and other forms of videography:
- Lighting, exposure and colors match the story, scenes, etc.
- Consistent skin tones and exposure over different shots.
- Consistent noise levels from shot to shot.
- Consistent colors from shot to shot.
- Consistent perception of exposure over camera moves from one exposure zone to another.
For a good overview of exposure, check this out:
Here are the six exposure tools, from worst to best:
6. Histogram
The histogram is pretty much the worst tool you can use to achieve the above objectives.
You can see where the image clips*, but if you only use that to match two clips, you can see quite easily in the video that won’t work under different lighting scenarios. Neither does ‘bunching up the histogram’ in the middle work, nor does ‘exposure for the highlights’.
If you want to know more about why histograms are not really useful, watch this video:
*Most histograms of cameras that shoot RAW don’t clip when the RAW signal clips. Still, it’s useful to know how a histogram works, because sometimes it’s all you get.
5. Zebras
The tool that makes up for what histograms lack is zebras. You can find relative differences in different shots because there’s a scale and band you can refer to that’s consistent across video formats.
Also, some cameras have a second zebra option for skin tones – though you’ll find most of them are limited to 70 IRE and up – which is only useful for lighter Caucasian skin tones.
The other problem with zebras is that they are hard to see in daylight, and the false color tool (see later) takes care of this. Zebras are not very popular today. However, if it’s all you have, then it’s worth your while to learn how it works.
4. In-camera Spot Meter
The in-camera spot meter is an extremely precise way to meter and nail the right exposure.
But you need a grey card to nail middle grey. And, you have to get close enough to get the area you want to spot greater than the 1-degree spot circle. You don’t get that luxury most times. And, you’ll hardly see grey cards on film sets. They’re just not practical for a variety of reasons:
- Grey cards don’t stay consistent when exposed to sunlight. The card you have on day one is not what you might have on day thirty.
- Grey cards are too small for telephoto and crane work.
- You can’t always position grey cards in the light you are exposing for.
- Cinematography exposure isn’t about middle grey, so most cinematographers don’t really care about it. Skin tones take precedence above all else.
3. Light Meter
A light meter can be an incident light meter or an incident + spot meter. This gives you the freedom to walk around, so you avoid the restrictions placed on you by the in-camera spot meter:
- You can walk around
- You don’t need a grey card
- You can spot or use the incident meter for lighting
Here’s more:
The big downside to the light meter is you need to calibrate it to the camera and format you’re shooting. Red vs Arri, you might have to change the way you meter. Log vs Rec. 709 vs HDR? You might have to change the way you meter.
It’s still a fast way to work, but with the next two tools, and the prevalence of video monitors, the light meter is being used less and less.
2. False Color
The most popular tool for cinematography today is the false color tool. It gets the job done fast and it’s sort of intuitive.
The false color tool is basically zebras but with color, and greater control over the entire range of IRE values.
There are two types of false color tools:
- The “rigid” system, where you can’t change which bands are what colors, or the range of each band. The fixed false color system is very limiting, because they, too, follow the old Caucasian skin tone preference, while ignoring the rest of humanity. And, you can’t use it for log modes because the IRE levels don’t match.
- Variable false color tool, used in monitors from SmallHD and FSI. With these tools you can change the range of bands, and even the number of bands so you can focus on what you like.
The variable false color is what I prefer and recommend. I can precisely dial in the range I want to see, and when the colors light up I know I have the right exposure. I can also dial in ranges for highlights, shadows or anything else I need. Matching becomes easy and fast. If you can, please buy monitors with customizable false colors. Here’s a good cheap one from SmallHD (Amazon, B&H):
Most DPs have at least two monitors on set for a film shoot, and more often than not you’ll see them exposing with false color.
If false colors are the most popular tool, then why is it at number two? Is there a tool that can do a lot more than false color?
Yes, and that tool is the scopes, or the waveform + vectorscope, which is at number one.
1. Scopes: Waveform + Vectorscope
The waveform monitor is a spatial graph that shows you the video from left to right, and all the ranges that fall on it. It’s like seeing the matrix, because you can see the entire range with the advantage the colors aren’t overlaid on the image.
You can have it small on the side, or full screen, or on another low quality monitor entirely. If you have only one monitor on set that the director needs, you can’t overlay false colors on it, but you can have a waveform in the corner.
With waveforms, you also have the advantage of seeing the range values all the time. It scales well for HDR workflows. It can work on any log profile. If the log profile says 41 IRE is middle grey, you just have to make sure the grey is at 41 IRE. If it’s 32 IRE, then 32. Split second, no customizations necessary. And because it’s a spatial representation if something blows you you can see precisely which part is blown out.
The waveform can do everything the false color tool can, but the false color tool is more intuitive because you can see the image. So to know the exposure on a face, it’s faster to follow a color than look at a graph. Some people are okay with graphs, many aren’t. That explains the popularity bit.
By the way, some monitors do allow you to crop the image so you can know the precise IRE value of any pixel. The scopes were built by engineers for precision.
What makes scopes the ultimate tool is its combination with the vectorscope. Not only can you see exposure information, but also color information as well. The skin tone line is not racist, and every skin tone falls on it. If you want to know if skin has unwanted color casts, this is the tool. You can also achieve color accurate videos with the vectorscope.
E.g., if Marvel demands Spiderman’s costume be pure red and blue, the vectorscope will tell you when you’ve nailed it. No other tool can do colors as quickly or accurately as a vectorscope.
Scopes are also found in color grading applications so if you learn how to expose with them, you can communicate easier with your colorists.
To learn how to use the waveform monitor, watch and read this:
Which exposure tool is best?
Just like they say about cameras, the best exposure tool is the one you have with you!
Sometimes you won’t have all the tools. E.g., The Sony a7III and a7S II offer only limited Zebras and an in-camera meter. The Panasonic GH5 has that and a waveform and vectorscope, but they’re too small! Some cinema cameras only have histograms and false color tools. Some high end monitors don’t have customizable false color tools.
Most cheap DSLR and mirrorless cameras only have histograms. I shot a project on the Canon 1D X Mark III with just the histogram, because that’s all I had. I also shot an entire feature film with just Zebras, because that’s all I had, too.
So, follow this rule of thumb:
Learn how all exposure tools work, and use what you like. That’s the smart thing to do.
What do you think?
