A tube unit for microscopes which has a tube lens, including two components with an intermediate, large air separation and an overall positive refractive power. The air separation is at least half the size of the focal length f of the tube lens. A roof edge mirror or another suitable deflection element is arranged between the two components of the tube lens. The roof edge mirror includes two mirrors which can be tilted with respect to one another, and which is able to be tilted around its roof edge. The tilting movement or the tilting angle of the tiltable mirror or deflection element corresponds to half the tilt or half the tilting angle of the tube or eyepiece viewing system.