Helios (lens brand)

Helios (Russian: Ге́лиос) was a brand of camera lenses, made in the USSR. They were usually supplied with Zenit cameras and thus usable with other M42 lens mount cameras such as the Pentax Spotmatic. Some later Helios models were built also for the Pentax K mount.

The Helios-44 and Helios-40 are derivatives of the Carl Zeiss Biotar optical formula.

List of Helios lenses

Helios Lenses from KMZ^{[cite 1]}
Model	Mount	Focal Length	Maximum Aperture	Minimum Aperture
Helios-2	M42	45mm	ƒ/2.0	ƒ/16
Helios-33	M42	35mm	ƒ/2.0	ƒ/16
Helios-40	M39, M42	85mm	ƒ/1.5	ƒ/22
Helios-40-2^{[exp 1]}	M42	85mm	ƒ/1.5	ƒ/22
Helios-44^{[exp 2]}	M42, K	58mm	ƒ/2.0	ƒ/16
Helios-53	M42	200mm	ƒ/2.5	ƒ/16
Helios-65	M42	52mm	ƒ/2.0	ƒ/22
Helios-70	M42, K	52mm	ƒ/1.9	ƒ/16
Helios-77	M42, K	52mm	ƒ/1.8	ƒ/16
Helios-81	F	52mm	ƒ/2.0	ƒ/16
Helios-85	M42	85mm	ƒ/2.0	ƒ/16
Helios-88	M42	50mm	ƒ/1.9	ƒ/16
Helios-97	M42	52mm	ƒ/2.0	ƒ/16
Helios-98	M42	28mm	ƒ/2.8	ƒ/16
Helios-101	M42	52mm	ƒ/1.8	ƒ/16
Helios-107	M42	65mm	ƒ/2.8	ƒ/22

^ The 40-2 is not truly a different optical formula, however its filter diameter was increased from 66mm to 67mm, and its tripod collar was made rotatable. This allows for easier mounting on some cameras. Reflective coatings have also been changed.
^ There have been many variants of the Helios-44 produced since its inception.