Is an LTM J-9 also usable on an M42 SLR?

[jamiewakeham]

Dear all,

I'm all confused. To be fair, it's quite late here and I may have had a glass of focussing fluid too many 🙄

I've hankered for a J-9 for a while, and offloading a load of Canon EF optics has allowed me to convince the significant other that I should be allowed to buy one.

I'd probably find it more useful on one of my Spotmatics than my Zorki, but I wondered if I could hedge this bet by getting one in LTM and also getting an LTM-M42 adaptor.

But does this work? Will an LTM J-9 on an M42 adaptor still focus to infinity, etc? I think it will; don't you simply have to shift the LTM lens away from the film plane to account for the greater register of an SLR?

Cheers
Jamie

 

[Ash]

probably just a matter of the shims like you're thinking. Either way its a portrait lens I thought, so infinity shouldn't be *that* important. If you use it to photo people within 10 metres you needn't worry about infinity - thats how I've always thought with slr's and conversions on lenses.

 

[Scarpia]

It will focus to about 15 inches at best. SLR's are simply not usable with lenses designed for rangefinders as their lens mounts are signifiantly further from the film plane than RF mounts. SLR lenses on the other hand can be used on RF cameras with the proper adapters but only with scale focusing. Some people do occassionally use RF lenses on SLR's for extreme macro work, however.
Kurt M.

 

[rolleistef]

But you can find m42 J9 can't you? They're pretty cheap!

 

[ray_g]

Different flange distance/register.

Your best bet is to get an M42 mount J9. Of all the J9 versions, this is probably the least expensive. Also less of a lottery that LTM versions when it comes to focusing accuracy.

 

[rxmd]

Maybe this should be an FAQ item, with a table, lens mounts on one axis, camera mounts on another axis, for each a short coloured field (infinity focussing yes/no, rangefinder operation yes/no) and maybe a link or explanation of the adapter necessary. And a good explanation of lens register.

Philipp

 

[AndersG]

Just get the M42 version for your Spotmatic. It is dirt cheap and quite good. I got mine for $30 in spotless like new condition. It is pure hell to focus on a 1.6x DSLR, though. Here is a sample taken at f/5.6 or f/4.0 with a D30.

Cheers,

Anders

 

[ZorkiKat]

The J-9 was made in many versions. There were at least 3 made for SLRs- for the Kiev with non-Nikon F mounts, M39 for the early Zenit, and M42 for SLRs like Zenit, Praktica and Pentax.

The M39 Zenit mount version could be used on M42 SLRs with an M39 > M42 adapter, but infinity focus is somewhat limited (maximum about 30+ metres). This is because the M39 Zenit lens register (also known as "working distance" in FSU literature) is slightly shorter at 45,2mm. The M42 SLR working distance is 45,5.

"Working distance" refers to the distance from the surface of the lens mount flange to the surface of the film. Different cameras have this at different values. LTM working distance is 28,8mm so the lens barrels of LTM lenses are longer. Mounting such on an SLR is like using a lens with an extension barrel, limiting focusing to extremely short distances.

To distinguish an LTM J-9 from a J-9 with M39 mounts for SLRs, simply look at the barrel length. J-9 meant for SLRs have short barrels- they look short and fat.

Jay

 

[oscroft]

But does this work? Will an LTM J-9 on an M42 adaptor still focus to infinity, etc? I think it will; don't you simply have to shift the LTM lens away from the film plane to account for the greater register of an SLR?

No, you have to move it closer because it's designed for a closer register than an SLR, and of course you can't do that.

 

[rxmd]

The M39 Zenit mount version could be used on M42 SLRs with an M39 > M42 adapter, but infinity focus is somewhat limited (maximum about 30+ metres). This is because the M39 Zenit lens register (also known as "working distance" in FSU literature) is slightly shorter at 45,2mm. The M42 SLR working distance is 45,5.

Where did you get that information? For all I know the lens register is the same 45.46 mm with the Zenit's M39x1 mount and the usual M42x1 mount. I have a friend with a Helios-44 in M39 for the Zenit that he's happliy using on non-M39 bodies with just a thin step-up ring, with focusing to infinity.

Philipp

 

[ZorkiKat]

Where did you get that information? For all I know the lens register is the same 45.46 mm with the Zenit's M39x1 mount and the usual M42x1 mount. I have a friend with a Helios-44 in M39 for the Zenit that he's happliy using on non-M39 bodies with just a thin step-up ring, with focusing to infinity.

Philipp

From the makers of the Zenit M39 lenses and cameras. I have two or three surviving "passports" for my ZM39 lenses which indicate that their working distance is 45.2mm.

Izaak Maizenberg also gave the same information in his camera repair books.

None of my Zenit M39 (Mir-37, Industar-50, Jupiter-9, Helios-40, Helios 44) lenses are able to focus fully to infinity as adapted lenses on M42 SLR cameras. Even the Russian users I've talked to
(one is a photographer who adapted some of his Zenit 39 lenses on his Praktica and Zenit M42) said this in the first instance when I asked him about adapting ZM9 to M42. He even sent me a translation from one of the booklets which say the same effect.

Your friend must be lucky to have his Helios really focus all the way to infinity.
This must be from a happy defect (bad shimming perhaps) which his current applications benefit from. The inability of ZM 39 lenses to truly focus to infinity on an M42 camera is a very slight one. Often, it is not very noticeable.

Jay

 

[rxmd]

Hi Jay,

I just crosschecked with Maizenberg (p. 226 in the English edition), it appears you are right.

Regarding my friend's Helios-44: I don't think you can get from 45.2 mm (+/- 0.02) to 45.46 mm by shimming, you'd have to take something off the lens. Probably someone did that. After all on a SLR the fineries of lens register aren't much of an issue because you can focus through the lens. This is interesting because it means that all those early model Helios-40's that are sold in M39 mount with M42 adapters aren't useable at all on M42 bodies.

Philipp

 

[AndersG]

This is interesting because it means that all those early model Helios-40's that are sold in M39 mount with M42 adapters aren't useable at all on M42 bodies.

That is not certain - it might be possible to move the infinity stop on the lens just enough to make up for the extra 0.3mm. I have done a similar adjustment on a Zenitar 16mm fisheye with a slightly too fat M42 to EOS adapter. But it all depends on the construction of the lens.

Cheers,

Anders

 

[jamiewakeham]

Oops. Of course I was wrong. Thanks for putting me right, guys.

I was simply thinking that I'd quite like to be able to use a J-9 on my Zorki as well. Ho hum. Could just buy two...

Cheers
Jamie

 

[ZorkiKat]

Hi Jay,

I just crosschecked with Maizenberg (p. 226 in the English edition), it appears you are right.

Regarding my friend's Helios-44: I don't think you can get from 45.2 mm (+/- 0.02) to 45.46 mm by shimming, you'd have to take something off the lens. Probably someone did that. After all on a SLR the fineries of lens register aren't much of an issue because you can focus through the lens. This is interesting because it means that all those early model Helios-40's that are sold in M39 mount with M42 adapters aren't useable at all on M42 bodies.

Philipp

The shims in my Helios-40 are quite thick. I would venture to assume that taking one off would "sink" the optical block far enough into the barrel to get a shorter register. The 0.3mm difference between 45.2 and 45.5 is not that great.

The adaptor also tends to add a bit more of length between focal plane and lens.

On the contrary, adapted Zenit M39 lenses function quite well - with certain applications- on standard M42 SLRs. For instance, Helios-40 and Jupiter-9 are often used in portaiture where ability to do infinity focus properly doesn't matter. Infinity focus isn't always necessary, and minute errors can always be compensated with the use of smaller apertures. After all does anyone really shoot distant vistas and landscapes at f/1,5? 😀


Jay

 

[ed1k]

Jamie,
J-9 lenses in m42 mount are still in production (well, they were some time ago for sure). You can buy a brand new one if you wish:
http://www.lzos.ru/en/optics_for_you/photo_camera_lenses/jupiter_9_lens.htm
Eduard.

Edit: Hmmm... I'm sorry. I just checked their on-line shop and there is no Jupiters there.