Unlike the threaded version of the MC Helios-44M-4, the bayonet version has a better assembly and a different diaphragm jumper drive. There are no optical differences.
- Focal length 58 mm.
- The maximum aperture is 2.0.
- The minimum aperture is 16.
- The number of lenses / groups is 6/4.
- The minimum focusing distance is 0.5 m.
- Resolution center / edge - 41/20 lines per mm.
- The number of aperture blades is 6.
- Coating type - multilayer MS.
- Optics bayonet mount - Pentax "K".
Design and ergonomics:
Iron and glass, as for a lens with aperture of 2.0 and focal 58 mm, MC Helios-44K-4 has a decent weight and dimensions. The factor is not critical. But the ergonomics are excellent, fingers intuitively find the controls. The focus ring is ribbed to prevent fingers from slipping. And the aperture ring, although it is located close to it, has a good thickness, which makes it possible to change the aperture value as comfortably as possible. The aperture switches in steps with intermediate values and characteristic clicks.
The diaphragm consists of 6 matte but not blackened blades. When aperture is applied, the petals form a hexagon, which negatively affects the "bokeh". A drawback appears in the form of the same hexagons in the background from light sources, popularly called "nuts".
The smooth course of the helicoid makes a little more than half a turn, about 210 °. From the minimum focusing distance to infinity, you need to make five intercepts with your fingers.
The main distinguishing feature of the MC Helios-44K-4 from other threaded helios is the bayonet mount to the "K" - Pentax camera. In the 80s, attempts were made at KMZ to automate the process of photography, namely, aperture priority and exposure metering at open aperture. It is extremely difficult to implement this function on threaded optics, for example Zenit-18 and its regular MS Zenitar "albino". One more point - the flange distance of 45.5 mm has been preserved.
Strict tolerance requirements for the threaded connection were required to achieve high accuracy and compatibility - which in turn made the process extremely expensive. And the bayonet connection does not require high specifications and provides excellent accuracy and compatibility of the device's diaphragm and lens drives. For the first time, Helios with a K mount appeared in the form of a standard lens for the Zenit-Avtomat semi-automatic camera (Zenit-14 is the same).
MS - not all Helios-44K-4 lenses have multilayer coating, but this sample has it and is not bad at all. Of course, the MC does not frankly support the backlight, but the side flares are not so noticeable. As always, a hood is recommended for any Soviet lenses. This type of enlightenment makes adjustments to the color rendition - the picture goes into cold tones.
Like most Gelius-44, the ends of the front and rear lenses of the G44K are not blackened. This fact has a negative effect on side exposure and backlighting, thereby making a negative contribution to contrast and resolution. The flaw can be corrected by yourself using a marker, get out the lenses and carefully sketch the ends.
MC Helios-44K-4 is able to draw sharp in the center of the frame and contrasting pattern starting from an open aperture of 2.0. A drop in the resolving power can be traced along the edges - which is normal for any high-aperture lens. On an open aperture, one can observe the twisting of the zone of confusion, the notorious twisted bokeh.
We should also mention portrait photography, the lens forms a contrasting and rich picture, pleasing to the eye.
MC HELIOS-44K-4 is an excellent fast lens capable of forming a high-quality image. The "K" bayonet connection allows this lens to be attached to any Pentax film or digital camera, without any restrictions. A hood is recommended, in some cases it will provide protection against side glare. Regarding twisted Bokeh, this is not for everybody, since there are those who like it and those who dislike it.