Exposure Triangle
Key points
Section titled “Key points”- ISO controls sensor sensitivity: low ISO (100) = darker, less noise; high ISO (6400+) = brighter, but more noise.
- Shutter speed controls how long light hits the sensor: fast speeds freeze motion; slow speeds show motion and risk camera shake.
- Aperture is the lens opening: wide (low f-number) lets in more light and blurs the background; narrow (high f-number) reduces light and increases background sharpness.
- The exposure triangle shows how aperture, shutter speed and ISO work together to balance brightness and creative control.
View the transcript on YouTube: Open video, then ••• → Show transcript
Please let us know if you have any feedback on this video, if you spot any issues that aren't already highlighted in the Nit-picking section, if you know of a video that could teach this section better, or if you think we need to produce our own version. If you particularly like it, please also leave a comment in the original YouTube video so the creator knows.
We'll be updating the current email option with an anonymous feedback form when time permits.
Exercises
Section titled “Exercises”Shutter Speed
Section titled “Shutter Speed”- Find something that moves (for example a running tap) set your camera to Shutter Priority (aka Tv or S) and take shots at a range of shutter speeds so that either the whole image is pin sharp, or the background is sharp but the moving thing is blurred.
- Note down the shutter speeds that got everything sharp, and those that had the moving thing blurred, did you have any shutter speeds where even the background had motion blur from camera shake?
Aperture
Section titled “Aperture”- Find or arrange a group of objects in a row, with some close to you and some far away, set your camera to Aperture Prioity (aka Av or A) focus on one in the middle of the range (not the closest to you, or the farthest) and try shooting them at a range of apertures.
- Note down the impact of the aperture on the depth of field, and how many objects were in focus.
- Go somewhere fairly dim (a windowless cupboard should suffice) set your camera to Programme mode (P) or if it doesn’t have programme, try auto, then take shots of something at the full range of available ISOs.
- Note down what ISO can you notice noise at when you’re zoomed in to the image at 100%
- Note down what ISO the noise becomes unacceptable in your opinion.
- Note down what ISO resulted in the camera selecting shutter speed that led to camera shake motion blur.