The Leica DMi8 microscopes feature a fixed bino tube and ergonomic tubesintegrated in the stand. The interpupillary distance can be adjusted accordingto the Siedentopf principle. The complex tube lens system is based onan infinite beam path. It converges the parallel beam path coming from thelens and forms the object in the intermediate image plane. Also, the tubelens system, together with the eyepieces, corrects the remaining image errorsnot corrected by the objective. The following applies to all tubes: Fieldof view 25 mm, eyepiece diameter 30 mm, a interpupillary distance range55–75 mm and a viewing angle of 45° (Fixed) or 30–45° (Ergo)