A:AnswerYes, the t7i has a mount for EF or EF-S lenses and this is an EF. Be aware that it will be subjected to the 1.6x crop factor (Canon) modification of an APS-C sensor, so this is effectively a 112-420mm lens on that camera.
A:AnswerAs someone who owns TWO Canon EF 70-300mm F4-5.6 IS Nano USM, - this lens should definitely work with the Canon T81 - I am using Canon EF 70-300mm F4-5.6 IS Nano USM, lenses with a Canon 60D and a Canon 80D body's
A:AnswerAs long as your camera is an EF Mount camera that uses EF Mount lenses then it should work fine. Even if it's a crop sensor camera, ef-s I think it will also work. The lens is really nice and takes very sharp quality images.