The Voigtländer VSL is a series of 35mm SLR bodies manufactured by Rollei in the 1970s and 1980s under the brand name Voigtländer. The name belonged to Zeiss before the demise of Zeiss Ikon in 1972, then was taken over by Rollei.
Rollei continued the production of the last 35mm SLR developed by Zeiss Ikon, the SL706 and called it Voigtländer VSL1. It could accept 42mm screw lenses. But it was a concurrent of their own 35mm SLR, the Rolleiflex SL35 and SL350, which used the Rolleiflex SL35 lenses. This absurd situation ended in 1976 when Rollei abandoned the development of its SL35 and SL350, and produced a variant of the VSL1 with the SL35 bayonet mount, called the VSL1 BM. The same body with modified cosmetics was called the Rolleiflex SL35M.
At the same time, the production was delocalized to Singapore. Only 500 bodies of the VSL1 (thread mount) were built in Germany, all the later cameras were assembled in Singapore. The rumor says that the quality control in the Singapore plant was poor at the beginning, but that the situation improved with the years.
The VSL1 existed in chrome or black, the VSL1 BM only in black. There was a name variant of the VSL1 called the Ifbaflex M102, only in chrome finish, made for a French distributor with an Ifbagon 1.8/50 standard lens (a rebadged Planar 1.8/50).
The same year was developed an automatic exposure version called the VSL2 automatic, and its Rollei equivalent the Rolleiflex SL35ME. The VSL2 automatic / SL35ME sold in parallel to the VSL1 BM / SL35M. All were sold only in black.
An elusive model called the VSL2 CX automatic did exist in very small quantities, and I have almost no information about it.
The next generation came at the end of 1977 with the VSL3E, the last Voigtländer body to be designed in Germany. It had an all-new electronic vertically running focal plane shutter, with flash sync at 1/125, and a SiO2 meter. Its Rollei equivalent was the Rolleiflex SL35E. They were sold in chrome or black.
The Vitoflex E would have been another model, equivalent to the Rolleiflex SL35OE Dual, with both aperture priority and shutter priority modes. However it would have needed a change to the lens mount. It was never released, and only a small number of Vitoflex E prototypes were built.
In 1981 Rollei went bankrupt. They had to close the Singapore plant, ceased the production of middle-range 35mm SLRs to concentrate on the high end Rolleiflex SL2000F, and stopped using the Voigtländer name.
To sum up: