Helios 44 mechanism

I've been looking into getting a helios 44 lens. I'm after one of the earlier models that has 13 aperture blades, and I keep finding versions that have this odd mechanism off to the side. There's many listing that have this feature, but no one describes what it is. I can't find any articles describing it. Does anyone know what this is? I don't want to buy one and find out that it causes some sort of incompatibility with my camera.

This looks Exakta mount to me. You should be able to find adapters for Exakta mount.

But Helios 44 in M42 will be easier to adapt.

I figured it out. It's a KMZ Start mount. It's like the Russian version of the Exakta mount. Finding a Start mount to Pentax K adapter seems like a long shot, so I should go with the M39 version.

Tumbles said:

I figured it out. It's a KMZ Start mount. It's like the Russian version of the Exakta mount. Finding a Start mount to Pentax K adapter seems like a long shot, so I should go with the M39 version.

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I've seen those referred to as "Z39" mount to emphasize the fact that the flange to focal plane distance is different from 39 mm rangefinder lenses. Easiest way to use is to get a 39->M42 adapter ring, and then you can treat it like any other M42 lens.

So I should get both a M39 to M42, and a M42 to Pentax K adapter, rather than a regular M39 to Pentax K?

There was a version based on an Exacta called 'Start'. The main difference was the technical sophistication not usual at the time (with some idiosyncrasies such as the mirror was wound down after exposure by a cord attached to the mirror) The Bayonet mounts are not interchangeable! The lens as you will have seen is a 58mm x F2 and like the Zenith lens, is probably based upon the Zeiss Biotar.

I had one of these around 1964. It came with a 39mm screw to bayonet mount and a manual apperture135/4 telephoto lens. I sold it to buy my 1st Pentax SV.

The Start is so old that I doubt if you will find a Pentax K adapter to fit. Getting a custom made mount will be actually quite expensive. The 'K' mount did not appear until the 70's when even the Zenith screw thread had changed from 39mm to 42mm. The auto aperture-come shutter release will not work on anything else. Not even an Exacta