1964, after Shanghai camera factory decided to export products, it registered the trademark "Seagull". Since then, all products produced by this factory have been branded as "seagull".

4 series 120 double reflex camera is one of the most famous seagull cameras. Its predecessor is the imitation machine based on Lulai Rolleiflex (about 1930) which was trial-produced by Shanghai Camera Factory in 1959.

The 4 Series 120 reflex camera has several large models such as 4A, 4B, 4C (rumored to be 4D), and each large model includes several small models. In addition, Shanghai Camera Factory used different brands when exporting to Japan, Germany and other countries, such as "Texer Automat" and "B.I.G Twin 4".