This video is part of our Intro to Photography series, where we break down some of the fundamental concepts of the image-making process. You can find a written version below. Intro to Exposure What is Shutter Speed? What is Exposure? What is Exposure? Exposure is perhaps the most important concept in photography.
The word 'photography' is derived from words meaning "drawing with light," so the amount of light your camera is exposed to is absolutely fundamental to the process.
What defines exposure?
Three factors define how much light your camera sees, and they're not necessarily the three you might expect:
Aperture value, or size of the hole through which your camera sees the scene
Shutter speed, or how long the shutter stays open to let light in
The amount of light in your scene
These three factors determine how much light hits your sensor. And that's arguably the most significant thing that determines image quality: how much light you captured to describe the scene. That's not quite the end of the story, though.
What about ISO?
Your camera also has a setting called 'ISO' that determines how light or dark your final image looks. So if you’re shooting in low light, you can increase the ISO to make the image look lighter. But be aware that changing ISO doesn’t increase the amount of light you captured: it just tries to make up for the fact you couldn’t capture more.
Pentax K-3 Mark III | Pentax 15mm F4 ED AL | ISO 32000 | 1/30 sec | F8
Edited in Adobe Camera Raw with noise reduction left to default
Photo: Carey Rose
As light levels fall, your images will get noisier, because of the lack of light. ISO can’t really help with that, but it’s not the thing causing the noise.
Shutter speed and aperture each have an impact on what the final image looks like. Once you understand those impacts, you can learn the balancing act required to get as much exposure as you can, then use ISO to try to make up the difference.
Intro to Exposure
What is Shutter Speed?
What is Exposure?
2025-7-20 16:00
