The calculation of Helios-65 was carried out in 1957 by the State Optical Institute (GOI). The task was to reduce the focal length of Helios-44 from 58 to the classic 50 mm.
Helios-65 can be considered an intermediate stage. The types of glass used in it are the same as in 44 Helios and in general the lens turned out to be not very successful.
Then the lens was once again recalculated for new types of glass on super-heavy crowns, and as a result, Helios-81 appears. Lanthanum glass allowed the new 81 to have quite decent performance.
Several lenses were produced on the Helios-65 scheme, which should be considered more like prototypes.
Here, for example, Helios-65 for rangefinder devices with M39 thread
And here is Helios-65Ts for Zeniths with a central shutter. The photo shows the lens on the Zenit-11. This device is very rare. It should not be confused with the later mass-produced Zenith-11.
Helios-65 was produced and more or less in large quantities. This was a variant of the Helios-65 Automatic machine for the Kiev-10 and Kiev-15 mirrors.
This lens was standard for the first issues of Kiev-10. The lens is now found on these devices. On my copy, for example, there is a cover with the inscription "Kiev-10".
I don’t presume to suggest the volume of such 65s, but it was not very large, since Helios-81 Automatic (on the right in the photo) appeared rather quickly and took the place of the regular ones.
Therefore, the Helios-65 Automatic machine encountered is still quite rare.
Now we are looking at a copy of the Helios-65 lens from 1965 under the number 65908.
- Focal length: 50mm
- Field of view: 45 °
- Frame size: 24 × 36 mm
- Number of lenses / groups: 6/4
- Working distance - 44 mm
- Aperture ratio: 1: 2
- Aperture scale limits: 1: 2–1: 22
- Aperture blades - 6
- Aperture adjustment - controlled from the camera
- Near focusing limit - 0.5 m
- lens with camera - Bayonet Kiev-Avtomat
- Filter Mount Location: Front
- Resolution according to TU (center / edge): 35/15 lines / mm
- Weight - 186 grams
The lens barrel is coated with glossy black paint. The coating of the later Helios-81 Automatic machine, in my opinion, is a little more matte.
Lenses Helios-65 Avtomat have a single-layer coating of violet shades.
The layout of this 65th completely follows from the type of fastening used in it.
The narrow, black knurled ring closest to the camera is fixed. It serves to hold the lens while attaching and detaching from the camera.
A little further from the body is the focusing ring. It is wide enough and comfortable. Focus is comfortable.
The full stroke of the helicoid is long - about 270 degrees.
There is a depth-of-field scale on the lens. But the aperture rings are not.
All aperture control is carried out from the camera.
Aperture blades 6 pieces. The petals of Helios-65, in contrast to the later optics for Kiev-Avtomat bayonet, are gray, not copper-colored. Although, the surface is glossy anyway.
There is information that both a small number of blades and their specific coating are all done to reduce friction when closing / opening the diaphragm.
This is the specificity of the Kiev-Avtomat bayonet. The camera's automation will only be able to control the diaphragm if it closes and opens completely freely. Without the slightest resistance.
As a result, distinct hexagons and the risk of parasitic re-reflections inside the lens are the main complaints about the optical properties of Helios-81 Avtomat.
The photo shows that the diaphragm blades converge with backlash, which is why the shape of the hole is regularly uneven. This feature is observed on all my Kiev-Avtomat lenses.
Apparently, this is also a price to pay for low friction.
Now the Helios-65 Automatic is more likely to be of interest only to collectors. Its non-standard mount and aperture control makes its use with modern cameras a task only for the keen enthusiast.
But if you are just an enthusiast and you are interested in looking at the picture that the 65th Helios gives, then a dilemma arises. All varieties of this lens, except for the Automatic, are super-rare, but the Automatic is relatively affordable and not expensive.
Therefore, it may be worth tinkering.
That's all for me, good luck!