three sliders, one balance.
The light in a scene is fixed; aperture, shutter and ISO share it out. Close one down and another has to open up — three sliders, one balance. Change the scene and see why the same settings now expose wrongly.
The distribution touches neither edge — detail survives in both shadows and highlights. This is what you are after.
Correct exposure is not one setting — three different routes reach the same light, and each route charges a different price. That is the lesson of the triangle.
The physics behind this bench, step by step: why three dials share one light, and which one to sacrifice when.
Read the guide →Engine: a real EV model, no list of ideal settings · photos: Unsplash