THE BLOG

Stops vs IRE: The Language of Cinematographers

Feb 16, 2026

Why Cinematographers Think in Stops (Not Just IRE)

Exposure vs Contrast

Most filmmakers learn exposure through tools like waveform, zebras, and false color. And to be clear, those tools are excellent. They help you place skin tones correctly, protect highlights, and keep your exposure in a safe range.

But proper exposure alone doesn’t create cinematic images.

Two frames can be exposed correctly and still feel completely different. The difference is usually contrast, the relationship between highlights, midtones, and shadows. When your lighting is intentional, you see depth, separation, and shape. When it isn’t, the image can feel flat even if the exposure is technically correct.

Insert image: Before/after frame grab showing flat vs intentional contrast

What Is a Stop?

At its core, a stop is a doubling or halving of light.

Double the light = one stop brighter
Half the light = one stop darker

Stops are not tied to a monitor tool or a picture profile. Stops are tied to physics. That’s why cinematographers use stops as a universal language on set.

Why 18% Middle Gray Matters

Stops are measured relative to middle gray. Every digital camera is calibrated around middle gray, commonly referred to as 18% gray. It’s called 18% gray because it reflects approximately 18% of the light that hits it, compared to pure white, which reflects nearly all of it.

Middle gray becomes the anchor point. When we talk about being one stop over or two stops under, we’re describing our distance from that reference point.

This is also why dynamic range is discussed in stops above and below middle gray. A camera might capture several stops above middle gray before highlights clip and several stops below middle gray before shadows lose usable detail.

Insert image: Middle gray card on set (BTS still)

Insert chart: Simple dynamic range graphic showing stops above/below middle gray

The Full Stop Table

Once you know the stop scale, cinematography becomes easier to repeat and easier to communicate. Here is a simple trick to remember full stops: memorize the first two values, 1 and 1.4, then double each sequence to build the table.

Full stop table

Stops Are Built Into Every Exposure Control

Stops aren’t just something your sensor measures. They’re built into the tools you use every day.

Aperture

Every time you change your aperture, you’re moving in stops. For example:

f/4 to f/2.8 = one stop brighter (double the light)
f/4 to f/5.6 = one stop darker (half the light)

ISO

ISO adjustments also move in stops:

ISO 400 to 800 = one stop brighter
ISO 800 to 400 = one stop darker

Even if you shoot at native ISO (or dual native ISO), stops still apply. In CineEI workflows, EI changes are measured in stops and guide how you expose.

Shutter Speed (and Shutter Angle)

Shutter controls how long light hits the sensor:

1/50 to 1/100 = one stop darker (half the time)
1/100 to 1/50 = one stop brighter (double the time)

Shutter angle works the same way:

180° to 90° = one stop darker
180° to 360° = one stop brighter

ND Filters

ND filters are also measured in stops. Instead of listing them verbally in the video, a simple visual chart makes this instant to understand.

Insert chart: ND stops table (including fractional and common cinema ND values)

Optional note for Sony FX6 users: FX6 variable ND begins at ND 1/4 (2 stops) when engaged, then allows precise control beyond that.

Contrast Ratios in Stops

This is where stops become a powerful creative tool. Contrast is the relationship between different brightness levels in your frame, and it’s measured in stops.

If you reduce the fill side by half, you create a one stop difference between key and fill. That equals a 2:1 ratio.

1 stop difference = 2:1
2 stop difference = 4:1
3 stop difference = 8:1
4 stop difference = 16:1

Each stop doubles the contrast ratio.

Contrast ratio example

Why I Bought a Light Meter

The truth is, you don’t need a light meter to create great images. False color and waveform can take you very far.

But if you want a precise way to measure different areas of the scene and define their relationships in terms of exposure and contrast, a light meter becomes the next step.

For me, the biggest shift was this: I’m not using the light meter to tell me what creative settings to use. I decide my aperture, shutter, and ISO based on the look I want. Then I shape the light to match those decisions.

Behind the scenes light meter setup

Incident vs Reflected Light

Most cinema light meters allow you to measure both incident and reflected light.

Incident light measures the light falling onto the object (using the dome).
Reflected light measures light bouncing off a specific surface back toward the camera (using the built-in scope).

Reflected readings make it easy to compare the bright side and shadow side of an object and measure the stop difference directly. That stop difference can then be translated into a contrast ratio.

Incident

Reflective

Protecting Highlights and Shadows with Stops

Once you start measuring in stops, you can place highlights and shadows with more confidence. Instead of guessing how close you are to clipping, you can measure how many stops above middle gray a bright area sits, and how many stops below middle gray your shadows fall.

This makes it easier to stay within your camera’s usable dynamic range and maintain consistency from scene to scene.

Waveform example

Final Thoughts

IRE helps you monitor exposure. Stops help you design light.

When you think and speak in stops, your lighting becomes more intentional and repeatable, and it becomes easier to communicate exactly what you want on set.

That’s why cinematographers think in stops, not just in IRE.

If you want to go deeper into camera settings and exposure control, check out my Essential Camera Settings course here:

https://www.cnomadic.com/essential