Ultron

Ultron is the name of a lens designed by Voigtlander, and later Zeiss. The name has also been used by the Cosina Voigtlander lenses.

Ultron 50mm f2.0 lens Voigtlander Prominent II image by Süleyman Demir (Image rights)

The original "Ultron" was a 50mm f/2.0 lens with 6 elements in 5 groups designed for the Voigtlander Prominent camera. It was designed by A.W. Tronnier as an improvement on his own Xenar (c.a. 1937) design. Ultron lenses were also used in the Vitessa cameras, Vito III, Vitomatic and others as a high end option over the Skopar.

When Zeiss took over Voigtlander a further design improvement by Tronnier resulted in the 50mm f/1.8 used in the Icarex camera and also available in M42 mount. This lens had an extra concave front element.
The same designed of the Ultron was also used for the Takumar 55/1.8.

Cosina Voigtlander

The name Ultron was reused in the early 2000 by Cosina for a 40mm f/2.0 Aspehrical lens, a 6 element in 5 groups lens for SLRs. Other lenses carrying the Ultron name include: a 35mm f/2.0, 35mm f/1.7, 28mm f/2.8 and Macro Ultron 35mm 1:2