The exposure triangle is one of the most commonly used methods for thinking about exposure, and while it is certainly very helpful, it is not perfect. This great video tutorial will show you a different way of thinking about exposure that helps encapsulate some information the exposure triangle misses or does not always make clear.
Coming to you from Andrew Marr, this helpful video tutorial discusses a different method of thinking about exposure. The exposure triangle is great for remembering the three elements of exposure and capturing some of the interactions between them, but one thing it does not do particularly well is represent the shifting balance between shutter speed, aperture, and ISO to create a correct total exposure. To better think about this, Marr advocates the usage of a circle that is divided three sections, one for each parameter. The idea is that an accurate total exposure is the full circle, and that, like a pie chart, each parameter's contribution is represented proportionally by the fraction of area it occupies in the overall circle. Changing a parameter shrinks or enlarges its portion and forces one or both of the other two to compensate in response. It's a useful method and a great alternate perspective if the exposure triangle doesn't work for you. Check out the video above for the full rundown from Marr.