Systems for optical diagnostics of plasma created in a plasma-focus device are described, showing progress in the development and application of different optical methods used in plasma-focus research. In the experiments carried out on the plasma-focus device at the Institute of Plasma Physics and Laser Microfusion, multiframe Iser interferometry and shadow photography, the Faraday rotation method, and high-speed photography in different spectral ranges were applied. The system used for investigation of the plasma structure and dynamics is fully automatic and is able to acquire images on 10 channels with time resolution of about 1 ns and spatial resolution of about 0.1 mm. Subnanosecond synchronization between different diagnostics was achieved. Some examples of recently obtained results are given.