Need help with enlarger lens thread size

Not too long ago I bought a
Schneider-Kreuznach Componon-S f/5.6 / 100mm Enlarger Lens
According to <this website> that lens should have a rear thread size of M32.5x0.5, and a front thread size of M40.5x0.5. I have verified the actual rear threads of my lens are, in fact, M32.5x0.5 as predicted by the linked chart - but I'm less certain about the front threads.

Because I am using this as a taking lens mounted on a bellows for close up photography, I want a lens hood on the front. But the 40.5 lens hood I ordered is too small. The lens hood - a cheapo eBay item - is stamped "40.5" - but it easily slips inside of the front threads of the lens.

My working asumption is that the generic eBay lens hood is mis-labled or out-of-spec, but I wanted to know if there are any Schneider-Kreuznach lens aficionados who can confirm or deny that this lens has a front thread size of M40.5x0.5.

Based on the Schneider data sheet in a later version it got at both sides 2 threads each.

At the front M40.5x0.5 and M43x0.75

The data sheet states M40, but there is no such thread and other Schneider lenses got M40.5, so the M40 must be a typing error.

AgX said:

Based on the Schneider data sheet in a later version it got at both sides 2 threads each.

At the front M40.5x0.5 and M43x0.75

The data sheet states M40, but there is no such thread and other Schneider lenses got M40.5, so the M40 must be a typing error.

Click to expand...

That seems to agree with the information on the Photo Cornucopia site (link in first post). Apparently two versions of the Schneider Kreuznach Componon-S 5.6/100 were offered: one was Leica threads in the back, and M43x0.75 in the front. The other version is the one I have.

I just noticed the Photo Cornucopia provides documentation - link to a Schneider Optics document - which confirms the above. That was all I needed, "official" confirmation that the Photo Cornucopia data is accurate.

Thanks.

runswithsizzers said:

Not too long ago I bought a
Schneider-Kreuznach Componon-S f/5.6 / 100mm Enlarger Lens
According to <this website> that lens should have a rear thread size of M32.5x0.5, and a front thread size of M40.5x0.5. I have verified the actual rear threads of my lens are, in fact, M32.5x0.5 as predicted by the linked chart - but I'm less certain about the front threads.

Because I am using this as a taking lens mounted on a bellows for close up photography, I want a lens hood on the front. But the 40.5 lens hood I ordered is too small. The lens hood - a cheapo eBay item - is stamped "40.5" - but it easily slips inside of the front threads of the lens.

My working asumption is that the generic eBay lens hood is mis-labled or out-of-spec, but I wanted to know if there are any Schneider-Kreuznach lens aficionados who can confirm or deny that this lens has a front thread size of M40.5x0.5.

Click to expand...

The source for that information is stated on the page itself but the link is also here http://www.photocornucopia.com/archive/75/vergroesserung_e.pdf so you can see the original data from Schneider. I'm not sure about any other versions of this lens and if you have a different version then please post a pic.

runswithsizzers said:

...
I just noticed the Photo Cornucopia provides documentation - link to a Schneider Optics document - which confirms the above. That was all I needed, "official" confirmation that the Photo Cornucopia data is accurate...

Click to expand...

That page is mine. The ENTIRE point of the page is to ONLY list data which has come from a verifiable or credible source such as the manufacturer or agent. There are times when I also add my own info, which I state, and this allows people to ignore it if they wish. Whenever possible I provide links to the data and when this isn't possible I cite the source so people can track it down themselves if required. I got sick of contradictory info and started the page many years ago and I update it when I get time or new data sheets, catalogues etc. or when errors are highlighted to me. But again, the ENTIRE point of the page is that the data comes from credible sources (not withstanding typos or errors in the original data which can happen).

There are hundreds of lenses which are NOT listed there simply because I don't have the credible data for them from the manufacturer or agent (which often appears in magazines as advertising). It's an ongoing project and if anyone wishes to contribute catalogues or scans of advertising pages etc. then please do.

jjphoto said:

That page is mine. The ENTIRE point of the page is to ONLY list data which has come from a verifiable or credible source such as the manufacturer or agent. There are times when I also add my own info, which I state, and this allows people to ignore it if they wish. Whenever possible I provide links to the data and when this isn't possible I cite the source so people can track it down themselves if required. I got sick of contradictory info and started the page many years ago and I update it when I get time or new data sheets, catalogues etc. or when errors are highlighted to me. But again, the ENTIRE point of the page is that the data comes from credible sources (not withstanding typos or errors in the original data which can happen).

There are hundreds of lenses which are NOT listed there simply because I don't have the credible data for them from the manufacturer or agent (which often appears in magazines as advertising). It's an ongoing project and if anyone wishes to contribute catalogues or scans of advertising pages etc. then please do.

Click to expand...

Thanks so much for providing a valuable resource! Because your web page displays much wider than my display, at first I did not notice the "References" column on the far right, so I was initially uncertain about the reliability of the data. I really appreciate your effort, and, especially, your commitment to providing verification - which is all too rare in these contentious times!

runswithsizzers said:

Thanks so much for providing a valuable resource! Because your web page displays much wider than my display, at first I did not notice the "References" column on the far right, so I was initially uncertain about the reliability of the data. I really appreciate your effort, and, especially, your commitment to providing verification - which is all too rare in these contentious times!

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Thanks. Good luck sorting out your hood.

It might be easier to get a generic metal hood in 52mm or 55mm and then use adapters from the lens to the hood. So once you have the right adapter for the lens the hood is usually the easiest and cheapest bit of the equation. That's how I do it.

jjphoto said:

The source for that information is stated on the page itself but the link is also here http://www.photocornucopia.com/archive/75/vergroesserung_e.pdf so you can see the original data from Schneider. I'm not sure about any other versions of this lens and if you have a different version then please post a pic.

Click to expand...

You gave your linked source the title "Taking Lenses", it must be "Enlarging Lenses".


Componon-S 5.6 100mm

older version
front M56.5x0.75
rear M50x0.75


newer version
front M40.5x0.5 and M43x0.75
rear M32x0.5 and 39x26

AgX said:

You gave your linked source the title "Taking Lenses", it must be "Enlarging Lenses".
...

Click to expand...

Thanks. This heading comes from within the Schneider pdf itself. It's not something that I've set or can change because I can't change the pdf.

The front thread of your 5.6/100 Componon-S is likely 43 mm x 0.75 mm pitch. That would explain why the 40.5 mm x 0.5 mm-pitch hood you obtained is too small.

Measuring the hole diameter can be useful. Ignoring the assembly clearance (rather small),

the hole diameter = nominal diameter – pitch

An M43 x 0.75mm pitch hole = 43mm - 0.75mm = 42.25mm hole diameter.

You can check this with a millimeter scale to determine the approximate hole size of the female thread.

Ian C said:

The front thread of your 5.6/100 Componon-S is likely 43 mm x 0.75 mm pitch. That would explain why the 40.5 mm x 0.5 mm-pitch hood you obtained is too small.

Measuring the hole diameter can be useful. Ignoring the assembly clearance (rather small),

the hole diameter = nominal diameter – pitch

An M43 x 0.75mm pitch hole = 43mm - 0.75mm = 42.25mm hole diameter.

You can check this with a millimeter scale to determine the approximate hole size of the female thread.

Click to expand...

I believe the version which has front threads in that size (43mm x 0.75mm) also has Leica threads in the rear. I know my lens is not Leica threaded (rear threads are verified to be M32.5x0.5), so I'm pretty sure I have the other version - unless there is some 3rd, hybrid version known to exist.

But, in the words of the American computer programing pioneer and Rear Admiral Grace Hopper: "One accurate measurement is worth a thousand expert opinions."

Unfortunately, today I am having a little trouble with the "accurate" part.

After 20-plus years of using my ELDI (Swiss-made?) vernier calipers, I thought I was confident of my ability to accurately measure within 0.1-0.2 mm. But today, measuring the outside of the male threads on the lens hood, I get 39.85mm. Measuring to the inside of the female treads on the front of the lens, I get 39.65 mm. Both measurements cannot be accurate, because the "bigger" lens hood easily slips into the threaded area of the "smaller" lens. Apparently, my calipers are not in agreement between the outside measuring jaws and the inside measuring jaws. (The two inside jaws overlap a few 10ths of a mm when the outside jaws are closed.)

So, one or both of my measurements are not to be trusted, but I'm pretty sure the inaccuracy is only a few 10ths of a mm and not 2 mm.

Assuming my lens has 40.5mm threads in front, I have ordered another 40.5 mm hood from a different source.