[reh321]

Hello!
I know there are a few threads here about M39 to M42 Adapter but I was not able to find a definitive answer to what I'm looking for:

I have a Spotmatic and would like to put a Jupiter-9 85mm lens (the first, silver version) on it. The lens has an M39 mount and it came with an Adapter to M42, which also looks exactly like the one he shows in the video at 7:09. On various Adapters to other lens mounts (Sony NEX, Canon EF etc.) it screws on nicely and the lens is great to use on these digital cameras. Focus to infinity is also possible.

However, on the Spotmatic it won't screw on properly, much like it is described in this thread.

So my question is: Does anyone know of an Adapter for M39 lenses to M42 cameras that will actually work on the Spotmatic?

Thanks for any suggestions!

Last Winter, I purchased a "Spotmatic" and a Soviet "Mir" 37mm lens at about the same time.
I thought the 37mm lens would be an interesting adventure even though I already had a 35mm Takumar,
but it wouldn't seat {screw all the way down} properly {so it wouldn't focus to infinity} on the "Spotmatic". Since I already had a 35mm Takumar, I told the seller what the problem was, and {when he had no solution}, I sent it back {I had purchased it via eBay} rather than diagnosing the problem, but I would guess the lens was actually a "Soviet M39" lens.

[kypfer]

Last Winter, I purchased a "Spotmatic" and a Soviet "Mir" 37mm lens at about the same time.
I thought the 37mm lens would be an interesting adventure even though I already had a 35mm Takumar,
but it wouldn't seat {screw all the way down} properly {so it wouldn't focus to infinity} on the "Spotmatic". Since I already had a 35mm Takumar, I told the seller what the problem was, and {when he had no solution}, I sent it back {I had purchased it via eBay} rather than diagnosing the problem, but I would guess the lens was actually a "Soviet M39" lens.

Nope … an M39 lens of whatever persuasion will simply "fall into" an M42 body and then rattle from side to side, the thread is far too small diameter to screw in at all.
If your Mir "wouldn't seat" there was some other mechanical issue, most likely a damaged thread or possibly a screw-head protruding from the back of the lens (if the Mir-1 has such screws). It's also possible that it was a Z39 lens with a faulty M39-M42 adaptor already fitted, much like the OP's original problem!

[Aejap]

Surely the Helios 44-2 is M42 fitting … the Z39 version is the Helios 44 (no -2)

Thanks for correcting me, you are of course correct!
I already had the 44-2 for M42 before, and I mixed the names up.

It's also possible that it was a Z39 lens with a faulty M39-M42 adaptor already fitted, much like the OP's original problem!

Well it doesn't have to be a faulty adapter. If the lens had one of these black M39-M42 adapter rings on it, it was exactly like my original problem. The adapter wasn't faulty, it just wasn't compatible with the Spotmatic. Using the original Asahi Adapter would have made medium to close-focus photography possible in @reh321's case.

[willdmo]

I have a cheapo thin metal adapter which converts between the two threads. the biggest pain is when it does not stay on the lens and gets "lost" in between lens and camera. Other than that, adapters made to specs work and the flange focal distance between "Zenit" 39mm and M42 is almost the same (Zenit is 0.04mm shorter or so)

[Aejap]

Hi willdmo,

I suggest you read my reply from earlier, all Information about this issue has already been said there.

the flange focal distance between "Zenit" 39mm and M42 is almost the same (Zenit is 0.04mm shorter or so)

Do you have a source for that assertion? All sources I found stated that M39 SLR is at 45.2mm and M42 is at 45.5mm, like I said before. The difference between 45.2 and 45.5 is like I already said 0.3, not 0.04, which is not that small a difference for flange focal distances.
Here is the manual of the Zenit 3m as a source for the 45.2mm (page 4, "Working distance").
M42 is a well known standard, but for example here is it's Wikipedia page as source for the 45.5mm.
I do not know how you calculated 0.04mm, but I dare to say that it's just incorrect.

(That's what I meant when I said

I hope that this will counter some of the misinformation that circulates on here and around the internet

by the way)

adapters made to specs work

Like I said in my mentioned reply from earlier, they do almost work. True infinity obviously can't be reached because the M39 SLR lens has to be closer to the film plane of the M42 camera than physically possible (no mechanical adapter can change that, there would have to be a correction lens inside the adapter). No adapter ring out there will make the lens screw 0.3mm further into the camera than possible.
Of course, that might not be that big of a deal for you, as it depends on what you want to do.

[willdmo]

screw 0.3mm further into the camera than possible

Yesm that us true on one hand, on the other I have a Helios 40 which is exactly this kind of m39 lens and I do hit infinity just fine wide open, let alone stopped down. The question is if the lens is made to specs or if it is made to m42 specs in the first place