Many photographers consider the lens to be the most important part of the camera–indeed, the lens determines how sharp your pictures will be and how much background blur you’ll have. In a way, the lens often determines the amount of noise you’ll have in your image, because a faster lens gathers more light, allowing the camera to use a lower ISO. For example, switching from an f/5.6 lens to an f/2.8 lens would allow you to use ISO 200 instead of ISO 800, reducing the visible noise in your pictures by 400%. That’s about twice the improvement you’d see if you upgraded your camera body from an APS-C camera to a full-frame camera. We test lenses rigorously in the real-world for different photographic scenarios, using scientific methodologies. To remain unbiased, we’ve never accepted money or free gear from any camera or lens manufacturer.