[RioRico]

When you have time, please provide us a product shot of your thin combo and I am eager to see your setup. I have strong interest in looking any small and pancake like lens that are reasonable in cost and performance.

Product shots will have to wait. I am packing for my annual migration from snow to sun. And you'd only see little silver lenses on a big black K20D. I guess my Argus adaptations might be of interest. But I can't promise anything soon. Cheers!

[hinman]

Product shots will have to wait. I am packing for my annual migration from snow to sun. And you'd only see little silver lenses on a big black K20D. I guess my Argus adaptations might be of interest. But I can't promise anything soon. Cheers!

Don't worry about the product shots? It is my solicitation to LBA thinking. It is best that I see less lens pictures (food for LBA thinking). I tried my other 3rd party adapter in removing the spring plate and turns the I50-2 to a permanent K-mount lens and the lens is actually more secure in the mounting. Shame on my two copies of genuine M42 to K adapter that have a little bit of play in the K-mount.

I did look up further on the Kipon M42 to K adapter and I don't see the advantages over the genuine or other 3rd party adapter. The latest Kipon adapter seem to have added an inner flange. The inner flange will help with M42 lens that does not have the A/M switch and push the pin to a retracting position that is equivalent to set the A/M switch to M position.

And I manage to find both caps and step up ring for 35.5mm and I will report back on lens hood that will work with I50-2.

Again, thanks to all for all the valuable inputs.

Warmest,
Hin

[RioRico]

I did look up further on the Kipon M42 to K adapter and I don't see the advantages over the genuine or other 3rd party adapter. The latest Kipon adapter seem to have added an inner flange. The inner flange will help with M42 lens that does not have the A/M switch and push the pin to a retracting position that is equivalent to set the A/M switch to M position.

I just decided that I need a Kipon M42-PK inner-flange adapter -- and I can't find any! Not available on Amazon, not for sale on eBay, not for sale by Kipon. What happened?

Again, thanks to all for all the valuable inputs.

No problem!

[hinman]

I just decided that I need a Kipon M42-PK inner-flange adapter -- and I can't find any! Not available on Amazon, not for sale on eBay, not for sale by Kipon. What happened?

No problem!

I can't find the Kipon adapter either. I have a contact in mflenses forum by the name of Alex who sold me a copy of M42 to K adapter with an inner flange, you can see more of my blog post on the adapter

• Blog post on M42 to K adapter with inner flange

There is a contact person in the blog post with email who used to offer a similar adapter in eBay.

Given how well you have done in lens modification, I will recommend doing the modification than getting the similar adapter. The aperture pin varies in length and distance away from the flange rim. The added inner flange may not work satisfactory with all automatic M42 lenses. The most frequent method of modification that I have done with good success is using a cut section of a ball point ink plastic tube to work against depressing the pin as shown below

Cheers,
Hin

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Last edited by hinman; 01-18-2012 at 03:28 PM.

[RioRico]

I can't find the Kipon adapter either. I have a contact in mflenses forum by the name of Alex who sold me a copy of M42 to K adapter with an inner flange, you can see more of my blog post on the adapter

I've tried contacting Alec before, with no reply. I'll try again.

Given how well you have done in lens modification, I will recommend doing the modification than getting the similar adapter.
...
The most frequent method of modification that I have done with good success is using a cut section of a ball point ink plastic tube to work against depressing the pin as shown below

My successful lens mods have been gentle butchery and little more. Mostly when I try disassembling lenses, they stay disassembled. I've tried the plastic-tube trick a couple times, with just ruined lenses to show for my efforts. So an adapter would be better.

[hinman]

Hi Jools, Hinman and RioRico

I have all 3 versions of this little lens, so have found these to work...


I-50-2 for M42. push on hood = 37mm dia. filter size = 35.5mm

A step-up ring of 35.5mm-49mm allows use of your choice of 49mm hood.


Cheers

Geoff

I do have both wide and normal metal lens hood on 49mm. I am looking everywhere for a 35.5mm to 49mm step up ring but my search come up short in ebay and those in BHphoto cost $20. On ebay, I do find 35.5 to 37mm step up ring and I may go that route and find a small normal lens hood for 37mm instead.

I will update when my items arrive.

Thanks,
Hin

[hinman]

I do have a general question on M39 mount. I have a M39 to M42 adapter and it looks just like a step up ring. In general, will M39 lens work on Pentax digital with two adapters stacked together as in M39->M42->K adapter ?

Thanks,
Hin

[RioRico]

I do have a general question on M39 mount. I have a M39 to M42 adapter and it looks just like a step up ring. In general, will M39 lens work on Pentax digital with two adapters stacked together as in M39->M42->K adapter ?

All the M39-M42 adapters I've seen are thin bands about 6mm deep, threaded 39mm inside and 42mm outside. I have zero trouble threading one onto an M39 lens, then screwing an M42-PK adapter onto it, and zero problem with infinity focus. (I mean Official Pentax or Bower-type clone adapters, the sort that normally allow infinity focus with M42 lenses.) That is exactly how I've mount(ed) my old Industar-50, and my Jupiter-9 and Jupiter-11.

There also exist wide- and thick-flange M39-PK adapters but these do NOT allow infinity focus with camera lenses like the I-50. I use those adapters to match L39 enlarger lenses to my PK bellows or tubes.

I should also mention that M39 infinity-focus problems can be solved by grinding-away a bit from a Bower-type clone M42-PK adapter. That's how I fit Exakta-mount lenses onto my K20D -- glue an M39-M42 ring around the Exakta bayonets, then use the thinned M42-PK adapter. No huhu!

[xjjohnno]

Hin, the most lilekly problem you'll have with M39 to M42 is if the M39 was built for the Russian rangefinders which have a shorter register to the Zenit M39. I have 3 lenses in my kit that are m39 and using those the adapters Rico has mentioned. 1 lens has no infinity focus while the others do and that's using the genuine PK M42 adapter.

[RioRico]

Hin, the most lilekly problem you'll have with M39 to M42 is if the M39 was built for the Russian rangefinders which have a shorter register to the Zenit M39. I have 3 lenses in my kit that are m39 and using those the adapters Rico has mentioned. 1 lens has no infinity focus while the others do and that's using the genuine PK M42 adapter.

In a related thread [ https://www.pentaxforums.com/forums/pentax-k-r-forum/172829-best-m42-screwmou...ml#post1795010 ] I summarized the 39mm thread situation. I note four types of lenses with 39mm mounts:

• M39, which have the same register (flange focal distance) as M42 and PK. These are almost entirely Russian AFAIK, made for Zenit SLRs; I've seen no others.
• LTM (Leica threadmount) which have a register much shorter than PK. These lenses CANNOT be used (without surgery) on Pentax dSLRs except for closeups.
• L39, common on enlarger lenses. These have no register. With the right extension (tubes and/or bellows) lenses longer than 60mm can reach infinity focus.
• A kind I've never encountered, don't know the name, not sure how they're used: 39mm thread, 0.75mm pitch. All the M39-LTM-L39 lenses have 1mm pitch.

Those LTM lenses with their Leica 28.8mm register, much shorter than the Pentax PK-M42 register of 45.46mm, means they'll never reach infinity focus on our dSLRs unless about 17mm is chopped from the lens body. Rotsa ruck. But they can be used on NEX or NX or m4/3 or Q or the new Ricoh GXR M-mountor. Start saving up, eh?

[hinman]

Much thanks for all the valuable inputs.

I tried the M39 to M42 to K stacked adapters on my K7 with my Industar-69 28mm f/2.8 in L39/M39 mount and the pancake lens can't seem to focus near or far. It is one of the pancake that I quite like in the Sony.

I will revisit all of your inputs and report back more.

From the RioRio list, I think my Industar-69 is either a LTM or a L39 lens. It can't focus at all with near or far objects. I will try on extension tubes and report back.

[RioRico]

From the RioRio list, I think my Industar-69 is either a LTM or a L39 lens. It can't focus at all with near or far objects. I will try on extension tubes and report back.

AFAIK the I-69 is LTM only, with a 28.8mm register. No good on any PK or M42 setup. Sorry.

[vitorp]

Hi all, my first time aroud here.
I just bought an Industar 50-2 M42 with case, front cap, but no rear cap, and I don't no the dia. for the rear cap.

can someone tell me the dia. for the rear cap??

thankyou!!

[bessa-66]

Hi all, my first time aroud here.
I just bought an Industar 50-2 M42 with case, front cap, but no rear cap, and I don't no the dia. for the rear cap.

can someone tell me the dia. for the rear cap??

thankyou!!

Any M42 lens cap will do

[Scottie1969]

I just bought an Industar-50-2 (M42 mount) and it come without either hood or front and rear lens cap.

The diameter of the rear lens cap is easy : any M42 rear lens cap will do, but what about the front ?

I keep reading that the filter size is 35.5mm, but mine seems to measure 33mm.

My lens seems to be made in 1972. Is that any indication for determining the correct filter size ?

33mm filters seem hard to find.