Not A Registered Trademark, but what is the "R" for???

All you Kodak historians please consider this question?

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I am still looking for a definative answer but this time I have a

photo. This is a 7 1/2" f:4.5 (190mm)Kodak Ektar that is Lumenized and

was year made in EI = 1948 and the production number is 423 but what

is the Large Capital <H4><B>"R"</B></H4>

 

I will also add that this lens does cover an 8x10 groundglass at

infinity but it is not a wide field lens? (Took two negatives today at

mid aperature of f:11 to get a good test.) I have been looking at

images of 7 1/2" Ektars for months and have not seen this mark on it?

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Thank You for your time, Paul<div></div>

<b>R</b>eally Fantastic Lens!

 

sorry, i don't know, but the commercial ekatars certainly are great optics!

Paul-

 

It's possible the "R" stands for Radiography (x-ray) and that the lens is optimized for medical radiography use.

Two good ideas and it is really nice and it does not glow in the dark, so I don't think radiography?

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I have also heard, Research, Registered, Reject and Rare??? Where is George Eastman when we need him!<br><br>

Thanks,<br>

Paul

Zeiss, Nikon and Canon all make lenses for radiography and use the "R" designation, or some form of the word "radiography" on them. I don't think it's necessary for the lens to glow in the dark for radiological use. :-)

I was just kidding about the "glowing" and I was not aware of the designation, so you may be on the right track? Would a color corrected lens in a shutter be used in radiography? Also are we discussing radiography as in x-rays??? Paul

Yes, its radiography as in x-rays.

 

I don't think it's necessary to have color correction for radiography (since x-rays are black and white anyway), but the lens could have been taken from an x-ray machine and put in a shutter. It's possible Kodak just pulled some of the lenses off the line and put the "R" on them and sold them for x-ray machines, color corrected and all.

 

 

Or, I could be completely wrong. This is just a guess on my part.

Well Dean, irregardless of right or wrong, it is an interesting idea and a whole new spoke in the wheel of possible meanings? Thanks, Paul

To the best of my knowledge... ALL X-ray images are made without any kind of a lens. The X-ray source is a point source, images -effectively- are shadows. No need for a lens.

 

Anyway, even if this weren't the case, since X-rays are so far removed from the visible spectrum, it's hard to imagine that such a lens would render a usable image in the visible light spectrum.

Hi, Bryce. "X-ray lenses" don't focus x-rays, they're typically very fast lenses used for photographing fluoroscope screens. Many lens manufacturers made them.

 

Regards,

 

Dan

Hello Bryce,

 

I just ask my beautiful bride of thirty years and you are right! Now I better explain, My wife is a veterinary technician and she has been using x-ray machines for a couple of decades. None that she has worked with had or have a lens.

 

Excellent point Bryce,

Thanks, Paul

Most x-ray machines used lenses to focus the light source. I'm not sure if that's still the case today though. X-rays definitely are not a point light source as you say. If they were there would be no need for the lead lined aprons the technician wears when he x-rays you. The rays would not spread any further than the patient.

Hello Dan,

 

So your point is that it would record a television monitor of some type? Like an ocilascope of some sort?

 

How have you been?, Paul

Holly molly!

 

X-rays are produced by bombarding a source material with electrons, and I think that target is relatively small and does indeed produce the rays from the equivilant of a "point" source although the rays then emerge in conical fashion and are shielded from further/wider dispersion by a dense material such as lead shields.

 

But I don't think this lens had anything to do with radiology...

 

Might this lens be designed for some sort of image projection? I don't have one any more to check but didn't some of the the slide projectors have lenses with an "R" designation (does "Rectilinear" mean anything to anyone here?). Could this have been either remounted in shutter, or perhaps designed for use in a graphics arts field?

Rochester?

Hi, Paul

 

Yes, that's almost it except the the fluoroscope screen isn't intended for direct viewing. The advantages of photographing a screen instead of exposing film directly are that magnification doesn't have to be 1:1 and that less x-ray exposure is required. High speed x-ray film exists, is double-coated, has emulsion on both sides of the support. I have difficulty reading fine details on it.

 

One other thought. All of the x-ray machine lenses I've seen or read about have been much faster than f/4.5 and much shorter than 7 1/2 inches. Typically f/1.4 or faster, some as fast as f/0.7, most under 4". So I'm not sure that your lens was intended for that application, 'R' or not.

 

Thanks for asking. I've been fine, continue to use and like my 160 Pro Raptar, continue to add lenses at other focal lengths. And you?

 

Regards,

 

Dan

Hello Dan,

 

After many delays I am just about ready to move my three enlargers into my darkroom. I have stacked up a bunch of 5x7 negatives and the 8x10 negatives are beginning to stack as well! Way to many delays but my old back tends to slow me down.

 

I obtain this 7 1/2" Ektar that is like a splinter I really want to find the answer! Plus a 12" Comm. Ektar and as a wonderful gift a 19" red dot APO Artar. Then without looking I stumbled upon a 270mm Red Dot APO Artar for $100! All of a sudden my lens kit has filled up!

 

So I just sent the shutters for the 10 3/4" Artar and the 12" Ektar for a cleaning and test. Along with a few other gems in my bag I plan to be using a wonderful 8x10 Eastman 2D all summer, films in the frig. bulk chemicals are in the boxes and the workspace is in sight. . .

 

Talk with you soon,

Paul

Hello Bill, yes that is very valid Rochester is a real consideration. Thanks, Paul

Found a pic of the same lens on *bay.

 

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&category=30076&item=7509922695&rd=1&ssPageName=WDVW

 

This one does not have the R, though. Does it look exactly like yours?

 

Paul

Hello Paul,

Yes the same thing, and you will also find one that is clearly mark wide field ektar. I even have the black box and two metal caps, an 8" cam for a pacemaker and the lens was mounted on a crown Graphic lens board.

As soon as I process the negatives I will know for sure but with the front and rear standard aligned on my 8x10 Cambo this lens appears to cover completely. With cut corners on the glass I can not say?

I will attach a small image for you.

Thanks, Paul<div></div>

Odder and odder. AFAIK, the 190 WF Ektar is f/6.3 and is a four element WA double gauss. The glasses are like this: ((|)), where | is the diaphragm. I bet your 190/4.5 is a tessar type. Look at it and tell us.

 

Cheers,

 

Dan

Dan,

 

This is a tessar design. BUT if you can give me something specific to ID I will look for it. The shutter is a standard Universal #4 and the diaphragm is located just behind the shutter blades. Fairly normal design I think.

 

I have more images if needed? Paul

Hello Dan,

 

I wanted to double check the lens design the lens appears to have 40mm wide optical surface front and rear as well as the same depth from center point a perfectly balance design front and back???

 

Paul

Paul, beats me.

 

Cheers,

 

Dan

The L inside the circle means the lens is coated.

 

R, I would guess, stands for repro (copying).