Help ID this tiny 1850s? Lens

[goamules]

Hi,
I've emailed a few lens experts and gotten no agreement on what these 2 1/4 inch long lenses are.
http://farm4.static.flickr.com/3309/3626978476_a6f1c63f0c_o.jpg

I got three of them, which were on sale from an estate along with a Holmes BH and a CC Harrison portrait petzvals. Because of this association, the ancient patina since cleaned, the fact that there were three, and the quality "rope-like" beading, I suspect they are gem camera lenses. But some aren't so sure.

Though there is no mounting threads, the elements are larger than the barrel. I've seen some older multi lens cameras where lenses are inserted into holes in a wooden lensboard. The focal length is about 4.5 inches, and notice the permanent stop at the end of the barrel. There is only glass in the one end. I see two reflections, the rear appears flat, the front convex. There is no way to remove the glass from the front fixture.

One had the stop removed, and it's pretty soft, not excessively so. Interestingly, it will cover halfplate at still life distances.

I'm thinking the lenses are: Gem or CDV, early American. Any other guesses?

[goamules]

Here is a later tintype multi gem camera that I think shows lenses just "press fit" into a board.

[goamules]

No one knows? Here are two halfplate collodion taken with the lens. It's apparent softness is more pronounced on the GG, but it is with my Verito too. Wet plate doesn't reveal as much.

http://farm3.static.flickr.com/2462/3637783064_e766e19046.jpg

http://farm3.static.flickr.com/2483/3637783054_34346eefca.jpg

Garrett

[eddie]

sorry. no help from me but lets see/hear the info on the Holmes BH and a CC Harrison portrait petzvals!

[goamules]

Well, I just got the CC, already had an HBH. This lens has a flared sunshade and is early. The problem? It's a somewhat uncommon "air lens", with two air spaces separated by more air. I got it for parts.....

[Peter K]

I got three of them, which were on sale from an estate along with a Holmes BH and a CC Harrison portrait petzvals. Because of this association, the ancient patina since cleaned, the fact that there were three, and the quality "rope-like" beading, I suspect they are gem camera lenses. But some aren't so sure.
Your lenses could be eyepieces for a microscope. Specially the diaphragm at the end remembers a "field of view diaphragm".

[Sevo]

Indeed. What is the exact diameter?

Sevo

[goamules]

"....could be eyepieces for a microscope...."

Well, they could be. But have you ever seen the eyepiece of a microscope that is 1" in diameter? The ones I've seen have a tiny, 1/4 inch glass, mounted in the center of a large, flat piece.

Also, what would be the purpose of the "steps" in the rim, other than to keep flare out of the lens? I.E. I think light was going in this part of the lens, not out.

The barrel is 1 1/4 diameter, behind the lens part. Here are more of the lens section.

[Peter K]

Well, they could be. But have you ever seen the eyepiece of a microscope that is 1" in diameter? The ones I've seen have a tiny, 1/4 inch glass, mounted in the center of a large, flat piece.
Toy-microscopes often are equipped with small eyepieces.

The "RMS" standard, decided by a coucil of the Royal Microscopical Society in 1899, is 0.9173" for an eyepiece. Most of the european lensmakers like Chevalier* and Oberhaeuser in Paris, Swift and Ross in London and Zeiss in Jena have made eyepieces with this standard long years before. But many other diameters where used also. E. g. the standard for eyepieces for stereo-microscopes is 30mm, 1,181". In the collection of the RMS one can also find older eyepieces with the diameter of 33mm and 34 mm.

An eypieces is in principle a loupe to magnifie the intermediate image made be the main microscope lens. Often two plan-convex lenses are used with the convex surfaces indictated to each other, a Huygens' eyepiece. But also an achromat is used in the direction of the eye, the field-of-view diaphragm near the plane of the intermediate image plane like with the Ramsden eyepiece.

Peter K

* BTW Chevalier was the lensmaker who made Daguerre's cameras.

[goamules]

Thanks for that info Peter. But I'm still not convinced these have anything to do with a microscope. Microscopes seem to have a flat eyepiece, with much smaller glass. Not a stepped "sunshade" type, like most lenses.