The Helios 40-2 85 mm f/ 1.5 (Russian: "Гелиос") is a fast lens with a fixed focal length for 35mm cameras with M42 screw mount.
With a special adapter can be attached to modern dSLR and mirrorless cameras.
There are two versions about this lens optical design origin. By one version it was based on Carl Zeiss Jena Biotar 75mm f/1.5 (1938 г., rangefinder system Contax I-III).
Other version rely on fact that first Planar's (fast cinema 35mm lens "Helios-1" 50/2, "Helios-2" 75/2 and "Helios-3" 100/2) were developed by GOI in may 1937y.
So it can be possible that Helios-40 was also developed by russian optical specialists.
As it was said before, Helios 40-2 85mm f/1.5 by its optical design is Planar (modification with thickened elements)
In aggregate of its technical data this lens suits better portrait work and art photography with a low DOF.
Helios 40-2 85mm f/1.5 provides enough sharp but not contrasting image. Colors are slightly faded.
The best feature of this lens is outstanding oil-painted bokeh at apertures F1.5-2. Background blurring has a noticeable "swirly bokeh" effect especially at F1.5.
Also you get a strong vignetting at this aperture value but at portrait work this cannot be considered as a problem cause it adds additional volume (tunnel effect) to the image.
It is very hard to focus at aperture value F1.5 even with "Lushnikov dandelion" and a special focusing screen (Split-screen + microprizm).
The best focusing results can be achieved by using LiveView with a great scaling.
Using Helios 40-2 85mm f/1.5 you have to consider one more feature of this lens - MTF curve dip in the middle between center and edge of a frame. This results in resolution drop in that area.
- Lens badly resists backlight and lateral light so lens hood is highly recommended
- lens is big and heavy
- focusing ring is located in wrong place thus it is not comfortable to use. Sometimes it rotates hardly.
Helios 40-2 85mm f/1.5 differs from Helios 40 by these parameters:
- Thread mount (Helios 40-2 has M42, Helios-40 has M39)
- Filter diameter (Helios 40-2 has 67mm, Helios-40 has 66mm)
- Resolution (Helios 40-2 has 36/17 lp/mm, Helios-40 has 32/16 lp/mm)
- Coating (Helios 40-2 has amber-yellow, Helios-40 has a violet color of coating)
- size and weight
In whole, amount of Helios-40 lens manufactured is much bigger than for 40-2. Though by assembling and optical quality best lens is considered to be Helios-40 which was manufactured before 1965 year. After this year you can find some very good copies but amount of rejects is also very big.
This lens shows better its potential with full-frame 35mm cameras.
Links to online resources:
Posted by: Sergei Borodin Date of publication: 27.07.2010