The DF 7x40 was produced during the 1960s/70's by Carl Zeiss Jena for the East German NVA. The DF is regarded by experts as the finest binocular ever made in Jena. The DF features an extremely robust and armored body, a ranging reticle which can be illuminated by a battery powered device and a detector for active infra-red sources, which is charged by the UV contribution during daylight. There are yellow filters for use under hazy weather conditions. These yellow filters are stored inside the of the plastic ocular cover. The eyecups are made of soft rubber and fold in so that the binocular can be used with gas-mask or glasses. The DF in service use, featured a leather strap attached to the central joint of the binoculars so the DF could be fastened to the soldier's uniform so there was some measure of stability while the soldier was moving. The DF binoculars were to be carried according to NVA regulation "at the man". It was forbidden for East German soldiers to rest the DF 7x40s on vehicles, indicating some measure of their value and the resources involved in manufacture.