Leica LTM Help Needed Identifying Filters

Leica M39 screw mount bodies/lenses
David Hughes

David Hughes

David Hughes
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It's that time of life when you start long term spring cleaning. I've some felt/velvet lined, slip on Leica filters in the box that I thought fitted the Summitar but they don't. They are a loose fit.

Casting around I discovered that they slip on, and fit nicely, a 43mm dia lens. Only I haven't one but the extension tube of the BELUN is 43mm dia! So it's an "A 43" but I didn't know such things existed...

The green one is marked "Gr." so no problems there but the two red ones are marked "R.h." and "R.m." and - if you glanced quickly at R.h. - you'd think it was a ND factor 8 or more; it really is very,very dark red.

So can any one out there in Leicaland identify the lens they slip-on to? and the type of filter and factor?

Many thanks in advance.

Regards, David
 
David, the Summicron 50 f2 DR, CV 24mm f4 (with the shallow hood in place) and CV 35 f1.7 Ultron all take the same Leica push on metal lens cap made for the Summicron DR and the DR has an outside diameter of 42mm. The lens cap has some felt flocking on the inside rim to give a snug fit, so your filters should be OK with these lenses. All of these lenses take 39mm (E39) screw-in filters, so assuming all other lenses with 39mm screw threads made by Leica have the same outside diameter, your filters could also fit Summaron-M 35mm, Elmar-M 50mm, Elmar-M 90mm and Tele-Elmarit 90mm f2.8

As for the red filters, it sounds as if the R.h might be infrared, but Leica called their Infrared Dark. Neither the Leica Manual and Data Book nor the Leica Advanced Photo School book make reference to the h or m suffixes.

All part of the Leica mystique!

Ray
 
From an old post of mine on Photo.net:

Rh would be "Rot Hell", literally bright red. Around 630nm, comprable to a Wratten 29.

Rm would be "Rot Mittle", literally average red. Around 670nm, comprable to a Wratten 70.

Rd would (I think) be "Rot Dunkle", literally dark red. Around 690nm, comprable to Wratten 87.
 
Thank you both; The R.m. version is the problem still, as I see it. My initial reaction was that the "m" meant middle/mittel but the lens really is in the welder's mask class. And it isn't made in a way that someone could have unscrewed the mount and swapped the glass.

So now I'm wondering if there were several grades of IR filter (as in a nominal light, medium and dark).

As for the size, I can't measure internally as the felt / velvet is the problem but they stack and so looking at the outer rim I've measured them and 42·9 to 43mm is the answer.

Perhaps ebay will be the final answer.

Thanks again, David
 
David Hughes said:
Thank you both; The R.m. version is the problem still, as I see it. My initial reaction was that the "m" meant middle/mittel but the lens really is in the welder's mask class.
Click to expand...

That goes for all filters in the old German nomenclature, the reds were very red by later standards.


David Hughes said:
So now I'm wondering if there were several grades of IR filter (as in a nominal light, medium and dark).
Click to expand...

These filters were not IR. IR film was not even about (at any rate for non-military users) before WWII.

Indeed, I've often wondered why their filters were that deep red. "Mittelrot/Rm" is quite usable with current film of the spectral response of 30's panchromatic films - but back then, it would have required a tripod given a factor of three to five stops on top of start speeds in the ASA 9-25 range. But "Dunkelrot" has upwards of eight stops attenuation with outdoor subject matter - I can hardly believe that these were used for anything other than process cameras. Quite probably the fact that these filters have survived almost as often a "Hellrot" indicates that they originally were rare, but were kept in a drawer, while the popular light red ones got lost or misplaced...
 
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Thanks Fokutorendaburando.

I'm not so sure about the availability of IR film; certainly I've seen pictures from the mid 1930's and it was used for "day for night" shots in cine then.

These oddments at the back of the drawers* etc certainly drive us mad. You'd be amazed at the time I've spent trying to find a lens it fits: measuring the OD of the BELUM knurled tube shows the desperation! I've also tried matching the engraving style and wording. For example, they all say "E.Leitz Wetzlar" but plain "Germany" only appears on one. That wording is identical to that on the clamp-on Elmar's filters.

I don't have this trouble with the ZWTOO's. It's all baffling...

Regards, David

* I've about 3 metres of shelving covered with things to be repaired or identified. Mostly the debris of 55 to 60 year's of photography.
 
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Maybe dark red had a bigger relevance in the use of the orthochromatic film that preceeded panchromatic.

But then I thought that ortho was more responsive to blue and less to red, hence the darker skin tones ?!? ...and isn't this the oppostite to the bias of Panchromatic

It would help if I knew what I was talking about or if I had time to defragment my memory!

Michael
 
Dralowid said:
Maybe dark red had a bigger relevance in the use of the orthochromatic film that preceeded panchromatic.

But then I thought that ortho was more responsive to blue and less to red,
Click to expand...

It is not responsive to red at all. But you might indirectly be right in that the price of deep red glass could have been cheap due to its widespread use as darkroom safety filter.
 
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Infrared film (and plates) were certainly available before WWII. "The Rolleiflex Book" published in 1935 has an entire chapter about infrared photography.
 
The Rm and Rh filters are definitely called out for IR film in my 1937 Leica manual set. Filter factors are given for a few brands of IR film with those filters.

I have a Kodak Wratten 89 in Series VI, and boy is that near-opaque!
 
Thanks everyone.

In the "Leica Accessories" brochure of 1935 they describe the red filters as light, medium and dense. Medium and dense being suitable for IR film. But it doesn't make sense to have R.m. on the darkest and R.h. on the light one. And the German word for dense also begins with a "D". Of course, there could be an even darker one but that would be impossible to use, to judge by this one.

Has anyone any ideas for the 43mm diameter lens it's meant for?

Regards, David
 
Maybe one of them faded? Written out, these were Hellrot (light red), Mittelrot (medium red) and Dunkelrot (dark red) - and seem to have had that colour at least back then.

The filters must not necessarily have been for a photographic lens - Leitz was, first of all, one of the top makers of scientific optical instruments, and IR and deep red sensitive/sensitized plates were widespread in astronomy and other scientific applications long before the first IR films appeared.
 
sevo said:
Maybe one of them faded? Written out, these were Hellrot (light red), Mittelrot (medium red) and Dunkelrot (dark red) - and seem to have had that colour at least back then.

The filters must not necessarily have been for a photographic lens - Leitz was, first of all, one of the top makers of scientific optical instruments, and IR and deep red sensitive/sensitized plates were widespread in astronomy and other scientific applications long before the first IR films appeared.
Click to expand...

Thanks, I wondered about that as I've binoculars and fields glasses with filter sets in the collection.

The other interesting point is that in the Leitz booklets the transmission curves are labelled "DR", "MR" and "HR" so "R.m." doesn't quite make sense. I've also read almost every catalogue from 1931 to '87 and have compared the Leitz NY ones with the Leitz Wetzlar versions.

As for fading, the lenses look very consistent across the glass, no hint of a shadow etc at the edges.

Thanks again, David

PS and they look like the "Intermediate collar" (FIRGI) without the slots shown in the 1930's catalogues and "Directions".

PPS (Edit) I shut the instruction book dated 5/1938 (LNY) and spotted a note to the effect that all Leitz lenses now have an IR index mark.
 
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Part of the Answer - Perhaps.

Part of the Answer - Perhaps.

There are some similar filters on ebay at the moment. I asked the seller about them and he said that they came with a Xenon 5cm f/1·5 lens. It was from 1939 according to the serial number.

So a little of the mystery solved...

Regards, David
 
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