The invention relates to a camera device for fastening to an eyepiece tube of a telescopic sight. For this purpose, a deflection module (12, 51) is fastened to the eyepiece tube by means of an assembly module (01, 50). A semi-permeable device (28) for deflecting the image from the axis of the telescopic sight is arranged in the deflection module (12, 51), which (28) enables a straight view through the device on the one hand. On the other hand, the image is deflected towards a camera module (34, 52) also arranged at the deflection module. The assembly module (01, 50), the deflection module (12, 51) and/or the camera module (34, 52) are detachably connected to each other.