What is exposure?

We simplify image exposure as a definition of our image being too dark or too bright.

An image contains two major components: the chrominance and the luminence.

The chrominance represents the colors and the luminance the brightness of an image.

So Let’s just focus on the luminance part as it’s the defining factor for our exposure.

A film scene will always have something in the frame that is either completely white or completely black and a range of grey tones inbetween. This is what we call the total tonal range of our image.

Imagine our tonal range as a scale that goes from black, 0% to white, 100%.

What we want is to measure for a specific grey area in our image to be at exactly 18% grey.

if we match this everything else will fall into place reproducing the image of our scene in camera as we perceive it in real life.

Thus Acheiving overall correct exposure.

Make sure to use on your photo camera or video camera “Evaluative mode” in order for your camera to take all pixels in consideration and get you the correct light metering of your scene.

Let’s look in our next blog post at what we technically need to do in order to achieve what we call correct exposure.