There is no information on the web for this, and the 2 related articles I found were incomplete and incorrect, so here it is for the record. [A modified Mir-26b 45mm f/3,5 on an unmodified Hasselblad 1000f] The Salyut/Kiev 'b" mount is very similar to the original Hasselblad screw mount on their 1600f/1000f cameras - no surprise because the Kiev was a copy. However, there are enough differences that you cannot properly mount a Kiev lens on a Hasselblad. There are not many working 60+ year old 1600f/1000f around (and the lens selection was meager for those), but there are a lot of inexpensive good Soviet lenses, some better than the overpriced Hasselblad equivalents. There are 3 main differences between the 2 mounts. 1 - length of the index pin - the Kiev versions being longer, sometimes too long. [Note: index pin on the Kiev (Left) sticks out further than on a Hasselblad (right)] 2 - The start of the helical thread is slightly shallower on the Kiev, so it does not engage the full 1/4 turn when the lens bottoms on the mount. [Note that 1) the Kiev mount (left) is deeper than the Hasselblad (right), 2) the thread does not extend as far into the mount on the Kiev (left)] 3 - The diameter of the base is slightly larger on the Kiev, so the lens can be tight in the Hasselblad's mount. I picked the Mir-26b 45mm f/3.5 because there were no wide angle lenses for the 1000f Hasselbald. A Fujitar/Kaligar 52mm lens was often adapted, but they were not that good. The Mir-26b is plentiful, inexpensive, and optically decent. And I had one handy that needed work. Here is the basic process. Remove the auto-diaphragm mechanism The Hasselblad requires manually set diaphragm, and the auto-diaphragm pin on the back of the Kiev lens interferes with the mirror box. The entire linkage can be reversibly removed from under the mount, it is held on with 2 screws. This mechanism is crudely made, and on my copy, was defective, not allowing the iris to close reliably/properly. Once removed, the diaphragm on my copy worked. Remove the mount registering pin This is the pin that allows the lens to lock onto the body, but because the threads are not the correct depth, you must rotate the lens further past the locking position to get the lens to mount correctly. And the pin is often too long, interfering with the mount and causing the lens to jam. You might have to sand the OD of the lens mount (the portion that inserts into the Hasselblad mount) a tiny bit as it is slightly larger and can interfere when inserted. Mine was a little tight, but usable, so I did not. That should be it. [Modified mount - removed index pin and auto diaphragm mechanism] Everything so far is reversible. Issues: I've only described the conversion for one copy of the Mir-26b, there are slight variation on this lens, and the other Kiev lenses are known to use completely different mechanisms in the mount. No locking mechanism - the lens is held on by the screw mount friction, I'd be careful walking around with it as it may come off. Thread engagement - when mounted to their respective bodies, this mount has a 1/4 turn from 3 threads engaged. Because the Keiv thread starts a little later, less than 1/10 a turn is engaged. This appears to be enough to hold the lens on, but as before, I would be careful walking around with the lens mounted on the body this way. [Test image: Mir-26b 45mm f/3.5 on a Hasselblad 1000f, expired Kodak PMC400] Counterpoint: If you only want to use the Soviet lenses, one is probably better off replacing the mount on the Hasselblad with the one from the Kiev, which should allow the lens to latch. I have not tried this yet, so I'm not sure what other incompatibilities are involved (I'll update this post if/when I get around to it). Or you can just get a Salyut/Kiev-88, the 88's also have an auto-diaphragm feature, which alone should make this decision. There are a lot of these on the used market, but the caveat is finding one that is working and adjusted properly. A lot of peoples adventure ends here, when they cannot get their body working properly - although this is also an issue with the 60+ year old Hasselblad. Going another step, you should consider the Kiev-88cm with the P-6 mount, which was made into the 1990's, and allows you to use a selection of nice Carl Zeiss Jena Pentacon-Six lenses along with the same soviet ones. I have all these. But this post is about mounting a Kiev-88 lens on a Hasselblad 1000f, in case you are interested in doing that.