Questions on "mystery" lens in M42 x 0.5 mount

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enricosavazzi
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Questions on "mystery" lens in M42 x 0.5 mount

Post by enricosavazzi »

I got a second-hand "mystery" Schneider industrial lens to test (which I will eventually discuss here, once I have learned something more about it). The first stumbling block came when I tried to mount the lens on a camera for testing. The lens has an M42 male thread, but neither M42 x 1 (the "standard" M42) nor M42 x 0.75 (the "standard" T mount). Instead it has an M42 x 0.5, which is new to me. It came without a retaining ring, so I am stuck.

Registration distance of this lens at infinity focus is roughly 26 mm, so much shorter than a standard T-mount lens. Still, in principle it could be adapted on a mirrorless camera. The lens does screw for about one turn into a standard-length T adapter, and in this case it focuses about 2 cm from the front filter mount. I don't have a shorter T adapter at the moment.

RafCamera has no M42 x 0.5 adapter in their catalog, and in any case I cannot get anything from them because Sweden is automatically sending back all incoming mail from Russia and Belarus (because of the war).

There used to be an eBay seller in Spain who (before Covid) used to make and sell lots of unusual lens adapters, but I cannot find him now on eBay. Does anyone know if he is still active, and if so, what is his eBay name? Alternatively, is there another EU-based maker of custom adapters who can manufacture one-off items at reasonable prices?

Does anyone know if the M42 x 0.5 mount has been used in the past for some enlarger lenses or large-format lenses?
--ES

Bakwetu
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by Bakwetu »

You mean https://customphototools.com/ ? He is Portugal it seems from his contact page.

enricosavazzi
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by enricosavazzi »

Bakwetu wrote:
Sat May 21, 2022 6:23 am
You mean https://customphototools.com/ ? He is Portugal it seems from his contact page.
Yes, thank you, this must be a seller I bought from multiple times in the past. I recognize several of the adapters and reversing rings that I bought years ago.
--ES

dickb
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by dickb »

If you are indeed looking for a spanish ebay seller, you may be thinking of this one:

https://www.ebay.com/str/microcrystal2013

He made or makes adapters in aluminium predominantly.

I have a few adapters from both the Portuguese and the Spanish seller. The last time I contacted the Portuguese site, a year or so ago, I got no reply, not sure whether he is still in business.

simplejoy
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by simplejoy »

Very interesting - I‘m looking forward to hearing more about this lens. I‘ve encountered 39x0.5 mm with Schneider enlarging lenses but never 42x0.5 with any enlarging/industrial lens so far.

I once thought the Agfa Color-Solagon DII 90 mm f/4.5 mentioned in my article (https://deltalenses.com/index.php/2022/ ... er-lenses/) had such a mounting thread but on closer inspection it turned out to not be a thread at all… the lines are parallel. Does the thread pitch look unusual as well?

It‘s possible that one of the Agfa Colostars has such a mount (there’s quite a variety there) but I don‘t own one that does.

enricosavazzi
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by enricosavazzi »

dickb wrote:
Sun May 22, 2022 6:51 am
If you are indeed looking for a spanish ebay seller, you may be thinking of this one:

https://www.ebay.com/str/microcrystal2013

He made or makes adapters in aluminium predominantly.

I have a few adapters from both the Portuguese and the Spanish seller. The last time I contacted the Portuguese site, a year or so ago, I got no reply, not sure whether he is still in business.
Thanks, I must have bought some microscope dovetail adapters from this seller several years ago, as well.
--ES

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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by Pau »

dickb wrote:
Sun May 22, 2022 6:51 am
If you are indeed looking for a spanish ebay seller, you may be thinking of this one:

https://www.ebay.com/str/microcrystal2013

He made or makes adapters in aluminium predominantly
I've bought a pair of adapters from him. Previously I contacted him asking for a custom adapter or a modification of one of them and he told me that he is not the maker, closing any custom option. The adapters came fast and are useful although the threads weren't mechanized with good precision.
Pau

enricosavazzi
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by enricosavazzi »

simplejoy wrote:
Sun May 22, 2022 11:38 am
Very interesting - I‘m looking forward to hearing more about this lens. I‘ve encountered 39x0.5 mm with Schneider enlarging lenses but never 42x0.5 with any enlarging/industrial lens so far.

I once thought the Agfa Color-Solagon DII 90 mm f/4.5 mentioned in my article (https://deltalenses.com/index.php/2022/ ... er-lenses/) had such a mounting thread but on closer inspection it turned out to not be a thread at all… the lines are parallel. Does the thread pitch look unusual as well?

It‘s possible that one of the Agfa Colostars has such a mount (there’s quite a variety there) but I don‘t own one that does.
It's a "true" helical thread in the Schneider lens.

Schneider machine vision lenses often come in finely threaded barrels that mate with a lockable adapter. This external thread is used for focusing instead of a focusing helicoid hidden within the lens barrel, and the threaded portion is typically 20-40 mm long. As you mention, some photolab enlarger lenses, especially from Agfa, use similar externally threaded barrels. In this Schneider lens, instead, the threaded portion is only 4.5 mm long and ends in an overhanging flat mounting flange, so I doubt it is meant for focusing. It is comparable to the mounting thread of the Printing-Nikkor 105 mm for example, but with a smaller diameter.
--ES

simplejoy
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by simplejoy »

enricosavazzi wrote:
Mon May 23, 2022 10:49 pm
simplejoy wrote:
Sun May 22, 2022 11:38 am
Very interesting - I‘m looking forward to hearing more about this lens. I‘ve encountered 39x0.5 mm with Schneider enlarging lenses but never 42x0.5 with any enlarging/industrial lens so far.

I once thought the Agfa Color-Solagon DII 90 mm f/4.5 mentioned in my article (https://deltalenses.com/index.php/2022/ ... er-lenses/) had such a mounting thread but on closer inspection it turned out to not be a thread at all… the lines are parallel. Does the thread pitch look unusual as well?

It‘s possible that one of the Agfa Colostars has such a mount (there’s quite a variety there) but I don‘t own one that does.
It's a "true" helical thread in the Schneider lens.

Schneider machine vision lenses often come in finely threaded barrels that mate with a lockable adapter. This external thread is used for focusing instead of a focusing helicoid hidden within the lens barrel, and the threaded portion is typically 20-40 mm long. As you mention, some photolab enlarger lenses, especially from Agfa, use similar externally threaded barrels. In this Schneider lens, instead, the threaded portion is only 4.5 mm long and ends in an overhanging flat mounting flange, so I doubt it is meant for focusing. It is comparable to the mounting thread of the Printing-Nikkor 105 mm for example, but with a smaller diameter.
I know it's been a while since this thread was started, but as a big fan of Schneider lenses I have to ask: Have you published anything about the mystery lens here or on your site (I wasn't able to find anything about it there, but maybe I just overlooked it) or are you still trying to gather more information? I would certainly be very interested to know.

enricosavazzi
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by enricosavazzi »

simplejoy wrote:
Fri Feb 03, 2023 3:49 pm
[...]
I know it's been a while since this thread was started, but as a big fan of Schneider lenses I have to ask: Have you published anything about the mystery lens here or on your site (I wasn't able to find anything about it there, but maybe I just overlooked it) or are you still trying to gather more information? I would certainly be very interested to know.
No, that project got sidetracked (and it is not the only one). I did not find any information on the lens, either. I wrote to Schneider and did get a reply, but no information, other than these prototypes had been made on special order for a customer. The Schneider employee who replied sounded surprised that these prototypes had somehow made their way into the second-hand market. From some details of the lens, especially the dual-band (NIR + cyan) dielectric pass filters mounted at the rear of the lenses, I slightly suspect they were meant either for remote sensing of vegetation, or for military/police surveillance.

One practical problem is that the focal plane is very close to the rear end of the lens barrel, so it was difficult to adapt the lenses and they can only be used on mirrorless cameras. Another problem is that the image circle is small and barely covers Micro 4/3. Adapting the lenses required the use of focusing helicoids with 65 mm front and rear threads. The lens sits partly hidden in the helicoid and the result is enormous, especially compared to Micro 4/3 cameras.

The lenses have a very high image resolution and no detectable geometric distortion. Another surprise is that they work rather well in UV imaging (in addition to VIS and NIR), although the rear filters they came equipped with do completely block UV and must be removed. I discussed some of my experiences with these lenses and published a few tests on ultravioletphotography.com:
https://www.ultravioletphotography.com/ ... ment-57261

I made the tests at the above link on a full-spectrum converted full-frame Sony mirrorless, hence the strong vignetting. One reason I did not continue is that there aren't many suitable subjects for UV imaging in the winter of central Sweden.
--ES

simplejoy
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by simplejoy »

Thanks a lot for the information and the link to your post - sounds very interesting! Even though there are some restrictions I‘m sure there are effective ways to use the lens, once winter is over (it‘s somewhat similar here - not much of interest outside here at the moment)!

Lou Jost
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by Lou Jost »

I live in a country where it is very difficult to get packages, so I often have to improvise. I have adapted lenses with odd threads (but standard diameters) very easily by using a small metal file to sand off the rekevant threads of a step-up or step-down filter (leaving some remnants to provide "bite") and then pushing this onto the lens, with good epoxy placed on the lens threads. Drastic but quite secure unless the lens is very heavy.

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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by enricosavazzi »

A couple of news about the "mystery" lens:

1 - I published a page on my site about the physical characteristics of these lenses: https://www.savazzi.net/photography/xenoplan26p1.html. I will publish lens tests on a separate page, but it will take some time. You can check my post on ultravioletphotography.com for preliminary tests (see my earlier post in this thread).

2 - There is right now at least one more lens of the same type available from the same seller, if anyone wants to take a bite. Search for eBay item 275349222529 . A word of caution is that the picture of the lens in the ad is not of the actual lens for sale, it is instead one of the specimens I own. Since my specimens have two different types of lens mount, contact the seller if you need to make sure what exactly they have available. I have no connections to the seller, other than purchasing three of these lenses in the past.

3 - I am posting this information only here and on ultravioletphotography.com.
--ES

Lou Jost
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by Lou Jost »

I went for the bait.

simplejoy
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Re: Questions on "mystery" lens in M42 x 0.5 mount

Post by simplejoy »

enricosavazzi wrote:
Sun Feb 05, 2023 6:13 am
A couple of news about the "mystery" lens:

1 - I published a page on my site about the physical characteristics of these lenses: https://www.savazzi.net/photography/xenoplan26p1.html. I will publish lens tests on a separate page, but it will take some time. You can check my post on ultravioletphotography.com for preliminary tests (see my earlier post in this thread).

2 - There is right now at least one more lens of the same type available from the same seller, if anyone wants to take a bite. Search for eBay item 275349222529 . A word of caution is that the picture of the lens in the ad is not of the actual lens for sale, it is instead one of the specimens I own. Since my specimens have two different types of lens mount, contact the seller if you need to make sure what exactly they have available. I have no connections to the seller, other than purchasing three of these lenses in the past.

3 - I am posting this information only here and on ultravioletphotography.com.
Thanks a lot for sharing your interesting article - a really fascinating lens!

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