Leica LTM Leica Screw Mount Wartime Fiducial Points

[Marc James Small]

I would appreciate some of the more knowledgeable foks here explain just what is a fiducial point and why there were used on Leica IIIcK cameras -- and why these were removed to "deface" the camera.

Thanks!

Marc

 

[Dwig]

What they are:

http://en.wikipedia.org/wiki/Fiduciary_marker

Why someone would remove them:

In cameras, these are usually in the form of triangular points along the edges of the image. They are either formed by a mask at the image plane, generally with one on each edge in the center, or by a reticle plate (glass plate covering the whole image with engraved cross hair lines). When done with a mask, the tips intrude into the image area and are arranged so that the distance between the tips is very accurately known and lines connecting opposite tips intersect at the exact optical axis. They show in all uncropped prints and provide a means of accurately determining the exact print magnification. That, combined with precise knowledge of the shooting distance and lens focal length, allows for accurate measurement of objects in the picture.

Since these little buggers stick into the picture and show on every print they are rather undesirable in a camera used for general photography. Removing them defaces the camera from a collector's point of view, but makes the camera usable for general photography.

 

[payasam]

Something like photogrammetry, Dwig?

 

[sevo]

They are reference points for photogrammetry, right.

 

[johannielscom]

Aha. Like the Hexars have, the compact Hexar has a triangular notch, the RF a round notch.

Anybody got a picture of these things on a IIIcK, or a scanned frame that shows it?

 

[rlouzan]

Hi Johan,

Here you go!

http://archive.liveauctioneers.com/archive3/westlicht.auction/10947/0032_7_lg.jpg

http://www.liveauctioneers.com/item/2667867

Regards,
Robert

 

[LeicaTom]

Hi Johan,

Here you go!

http://archive.liveauctioneers.com/archive3/westlicht.auction/10947/0032_7_lg.jpg

http://www.liveauctioneers.com/item/2667867

Regards,
Robert

Yeah, I remember when #391627 K was sold......very interesting camera 🙂

Tom

 

[Marc James Small]

Thanks, guys. Now, which system did Leitz use -- a mask over the film or a Reseau (glass) plate? Bear in mind that fiduciary points may be well known to some of us, but others in our number may not know of them. Always try to explain simply but fully.

Marc

 

[photovdz]

to be usable, you need to know other variables such as focal length (exact one), and focus distance...
The best known photogrammetric system is the rollei metric system with rollei 600x with special refered optics...
there is also a rollei 35 T metric... sort of geometre toy...

For the leica with fiducial marks I must suppose that there are special lenses to be used with those cameras ? how to spot them ?

 

[Marc James Small]

We have a number of folks among our number who are experts on the IIIcK line. Until this discussion started, I had had no idea that these cameras originally had fiducial point mechaniisms of any sort. Now, can LeicaTom or one of our other IIIcK scholars tell us exactly WHAT Leica used? Was it a mechanical device or a Reseau plate? Enquiring minds want to know!

Marc

 

[photovdz]

It seems that the frame itself + two arrows play the role of fiducial point. no need for any other device... but it would only be useable with calibrated lenses as you must know the exact focal length (and the focusing distance which is modifying the focal length) of the lens in order to calculate any distance, size etc...

(I did some photogrammetric work... in the past)

 

[jan normandale]

for Marc James Small, online resources:

http://www.lhsa.org/
http://leica-users.org/

 

[Marc James Small]

I ask a simple queston, and people seem to want to be complex in their answers. Did the Leica IIIcK employ a mechanical fiduciary point or a reseau plate? Seems a VERY simple matter to answer!

 

[Dralowid]

Mechanical. They are simply metal points on the metal frame surrounding the film opening which would have left a clear image on the film. I have no knowledge as to what they were used for except possibly for simple and quick centering of negatives in an enlarger or as a previous poster menationed, to give an accurate measure of enlargement. I question that they would have been used for measuring/mapping/recon purposes after all there are too many other variables (lens/subject distance etc) and frankly 35mm is not the format one would choose for such a purpose.

To make this all more relevant and controversial, research the moon landing photos and the arguments regarding their veracity and the veracity of the landings themselves driven by someone's study of the overlaid grid (reseau plates and Hassleblads that are still up there I think)... the whole thing must be spelt out on the interweb somewhere

Michael
(who knows nothing)

 

[sevo]

As far as I know, reseau plates did not make it down to generally available hand held cameras until Rollei introduced their small format photogrammetry system in the seventies/eighties. This was a more of a matter of evaluation soft- and hardware than of the cameras or optics - only the NASA had a application where the transport cost made it reasonable to mate a cheap small camera with high end mainframe computers and project specific software.

 

[Marc James Small]

Thanks, guys. Hasselblad used Reseau plates on the Hasselblad cameras it made for NASA in the 1960's. long before Rollei got seriously into photogrammetry.

So, the Leica IIIcK came with a metal plate in the film opening with notches which would show up on the negative. Not sure WHY they would have done this, but, then, so be it!

Again, thanks!

Marc

 

[johannielscom]

Hi Johan,

Here you go!

http://archive.liveauctioneers.com/archive3/westlicht.auction/10947/0032_7_lg.jpg

http://www.liveauctioneers.com/item/2667867

Regards,
Robert

Marc,

Robert posted these links earlier on, you may have missed them. They show the exact 'construction' of the points.

I reckon that when the focal length of the lens is known, the size of the points can be taken as a steady indicator, and size or distance of objects photographed can be determined. Focusing distance probably would rarely enter the equasion, as most photographed objects would be shot with the lens at infinity anyway.

 

[sevo]

So, the Leica IIIcK came with a metal plate in the film opening with notches which would show up on the negative.

Not notches, points! Whatever it may have been used for may not have been too successful, as it did not receive any post-war publicity - the Germans were on a perpetual, but mostly unsuccessful search for the war-winning "Geheimwaffe" and were not too keen on publishing their failures...

Sevo

 

[LeicaTom]

Mechanical. They are simply metal points on the metal frame surrounding the film opening which would have left a clear image on the film. I have no knowledge as to what they were used for except possibly for simple and quick centering of negatives in an enlarger or as a previous poster menationed, to give an accurate measure of enlargement. I question that they would have been used for measuring/mapping/recon purposes after all there are too many other variables (lens/subject distance etc) and frankly 35mm is not the format one would choose for such a purpose.

Michael
(who knows nothing)

Michael and Marc,

Artillery Units supposedly used them together with the Elmar f3.5/50 (the original issue lenses) ~ perhaps Jim Lager would be the person to ask about this, as these points were only seen inside the W.H. (Wermacht Heer) stamped Grey K shutter cameras in orders made after June 1943.

Most of these cameras were captured by GI's, Russian and Commonwealth forces and if "used" as a normal camera shooting, the owner would just file the points off and then you have the original 35mm film plane, cameras that were kept as war trophies, STILL have these marks/points so they survived as were original.

Marc, do you know of any of the many strange Leitz finders that were made during the war? These were something that was made for combat use as were those strange points, have you seen anything else that was made during the war that was'nt normal at Leitz?

Tom

 

[Marc James Small]

I have a fair amount of knowledge about the German optical industry during the Second War but very little knowledge of the specifics of the equipment, I fear. I am aware of the ELNY multiple viewfinders but I now very little about German produced military gear. Certainly, these were not commonly used, as very few Leicas were used by combat photographers to my knowledge. You and Jim know a lot more about such items than do I!

Marc