The Russian Helios 44 58/2 lens has received a lot of raves on this site and is somewhat of a cult classic. As many of you are aware the Helios 44 is based on the optically similar Zeiss Biotar 58/2 and is available in a number of different variations based on mount, manufacturer, and diaphragm automation.
Most of the happy Helios owners on this site have one of the M42, automatic aperture versions (44M, 44M-x) or the earlier 44-2 with preset aperture. Although these are the more common variants, there is another version with pre-set aperture, the 44-3, that is highly regarded. The Helios 44-3 often features multi-coated optics and was manufactured well into the 1990s by the Belomo plant. While this lens is desirable, the potential buyer should be aware of a serious compatibility flaw with some (not all) Helios 44-3 lenses.
The Helios 44-3 was originally designed as the normal lens to be shipped with various Zenit 35mm SLR cameras. These bodies have a M42 lens mount with an unusually narrow body flange to accommodate the focus ring on the Helios 44-3. Now you are scratching your heads and muttering "huh?"...let me explain further. The focus ring on a pre-set lens is nearest the camera body with the aperture ring being towards the far end of the lens. On some models of the 44-3, the focus ring nests OVER the lens mount. Here is a picture:
The above lens was made in 1986. With many non-Zenit M42 bodies as well as all K-mount cameras (adapted), the focus ring will not clear the mount face on the body to allow for a clean mount. The fix is to machine the back of the focus ring down a couple of millimeters so that it is forward of the mount flange.
Note that this is not true of all Helios 44-3 lenses. The physical design varied over the years. So...before you contract to buy from a Russian or Eastern European seller where a return might be difficult, be sure to request a detailed photograph of the lens mount from the side.
Edit: Apparently date of manufacture is not a reliable indication of whether a lens has the incompatible design. At least one example made in 1994 has the issue (reported by lens owner on the Flickr Helios 44 group).
Steve
(Almost plunked down a few rubles for the above lens before I noticed the mount...)
Last edited by stevebrot; 06-06-2012 at 09:06 AM.