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Helios lens

Vega-3C 2.8/50

A normal lens for SLR cameras with a C mount (Zenit-4, -5, -6).Vega-3 is one of two real-life lenses for the Soviet Ts bayonet. The second is Rubin-1 2.8 / 37-80.
Several more models of lenses were supposed to be produced for this type of mount, but if they exist, then in single copies.

The whole technique for the C mount is very interesting. I recommend checking out the related reviews on my blog.
  • - Zenit-4
  • - Zenit-5
  • - Zenit-6
  • - Rubin-1Ts 2.8 / 37-80
  • - Mir-1C 2.8 / 37
  • - Bayonet C

But back to Vega.

It was produced only at KMZ. The lens is standard, very small. If we compare only the part protruding beyond the camera, then Vega will be shorter than Industar-50-2.

Vega-3 was produced in several design options. About 5 copies passed through my hands, so there were literally no two completely alike among them.

Although Vega is not a very rare lens, there are not many photos taken through it. This is due to the fact that the Soviet Ts bayonet is incompatible with any modern types of mounts or adapters.

Geometrically, the bayonet is quite similar to the German DKL, but the flange distance is not exactly the same. And it is not a fact that the diaphragm will be controlled.

I am using a homemade M42 thread adapter with aperture control function.

Optical design:

  • Focal length: 50mm
  • Field of view: 45 °
  • Frame size: 24 × 36 mm
  • Number of lenses / groups: 5/4
  • Working distance - 47.58 mm
  • Aperture ratio: 1: 2.8
  • Aperture scale limits: 1: 2.8–1: 22
  • Aperture blades - 5
  • Aperture adjustment - blinking, controlled from the camera
  • Near focusing limit - 1 m


  • lens with camera - Bayonet C
  • for screw-in bits - M40.5 × 0.5
  • for slip-on attachments - ∅42 mm
  • Filter Mount Location: Front
  • Resolution according to TU (center / edge): 55/21 lines / mm
  • Weight - 100 grams
  • Enlightenment is present - violet shades.

Vega's layout is rather unusual.

The ring closest to the camera is fixed. It serves for holding the lens while attaching and detaching from the camera.

The next ring is a focusing ring, it is very narrow. Sometimes it is supplied with a narrow knurled edge, and sometimes with a plastic leash from below.
The full stroke of the helicoid is small, about 170 degrees.

There is no aperture ring on the lens. The aperture is controlled from the camera by a ring around the base of the lens. The diaphragm is blinking.

The diaphragm petals are black, there are 5 of them, and they form distinct pentagons.

The most interesting thing about Vega is the depth of field scale. Designers for optics under the C mount tried to create a system of automatic indication of depth of field.

It looks like 2 red markers, on either side of the risk, indicating the distance.

Markers are movable. When you rotate the aperture ring on the camera, they move and move apart, cutting off the depth of field corresponding to a given distance and aperture.

It looks just magical.
But due to the fact that Rubin-1 is a zoom lens, and on it such a task is not solved in principle, and other lenses under the C mount, if anyone saw it live, then it is time to show it in the museum itself - then Vega-3 , this is the only lens encountered with such a depth of field indication system.

The back cover of Vega is also interesting. It is not put on the mount, but on the frame of the rear lens. Therefore, the cap is very small. :about)

Should you buy Vega for your digital camera?

Are you seriously? :about)

The lens is good. Sharp at low apertures, with interesting blur. On a fully open one, it is very soft.

In general, Vega has no advantages over the whole army of later Soviet fifty dollars, so squats with a C-mount are the lot for enthusiasts.

That's all for me - good photos!

Test shots:

The pictures are arranged in three. The first is with a fully open aperture. The second one is covered. The third one is heavily covered, but not to the limit.

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