How is video quality on Canon Rebel t5i, t4i?

I will be shooting video from a distance (about 40-50 yards away from the person) so if i use a 55-250mm lens would it still be HD?

For clarity, HD is a term for video and refers to a video frame which is 1280 x 720 pixels (about 0.9 mp of the pixels on any camera. The Canon T4i (long discontinued) and T5i both have a 16 mp sensor, so when shooting a video in HD, only 1/16th of the available pixels are used.

When I'm shooting an object that is from 40 to50 meters from my location, I use a long telephoto lens, like a 300 mm mounted on my APS-C sensored Nikon D500.

If I were to shoot video with my camera, the focal length of the lenses I pick will not be any different from those I use when shooting stills. The focal length will depend upon the subject's distance from the camera as well as the expected path of the object if it is moving HD is a video resolution term and has absolutely nothing to do with image quality or lens used. HD is a video standard that concerns mostly size/resolution. Video quality depends on your skill. The camera is only a tool. You will get the same result no matter what camera you choose.

HD is a video resolution term and has absolutely nothing to do with image quality or lens used.

HD is a video standard that concerns mostly size/resolution. Video quality depends on your skill. The camera is only a tool. You will get the same result no matter what camera you choose.