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MYSTERY 100 Y O BRASS LENS


THOMAS BOND
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Well, at the risk of stating the obvious, it simply appears
to be a barrel lens of the type typically used on view cameras
since the earliest days of photography itself.

There's no shutter or focusing mechanism, because both of those
functions are located elsewhere on a view camera. Well, shutters

were separate in earlier cameras, anyway. Modern view camera

lenses usually have leaf shutters built into them.

The speed range only begins at f/8, so the lens arrangement is a simple
one, probably a symmetrical doublet.

Can't tell focal length, or anything else besides this, just by looking.
You could determine focal length with a simple optical bench test.

Manufacturer, age, collectors' value? You need a real expert for that.

Edited by dan kessler
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Can't tell focal length, or anything else besides this, just by looking.

You could determine focal length with a simple optical bench test.

 

 

Silly me, we can get the focal length by measuring the diameter of

the aperture at f/8, then doing this calculation: f.l. = dia. X 8

Edited by dan kessler
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As others have stated, it looks like it's from the early days of still photography. The fact that the f-scale goes all the way up to f/64 and that there is no focus ring (as someone else observed) gives even more credence to this theory. It makes me think it was used for photography where there were wide open, sunny landscapes - like the Wild West.

 

But there are plenty of real lens experts on here that can tell you much more...

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Very likely a Rapid Rectilinear (or Aplanat) copy, they were very popular lenses from their invention in 1866 right up to the First World War, and generally made as an f/8 lens.

 

Although iris diaphragms were a much earlier invention, they weren't in widespread use until around the mid 1880s.

 

So to guess a date I would say somewhere between 1885 to 1910.

 

The focal length can be easily estimated by measuring the apparent diameter of the wide open aperture as seen through the front, and multiplying by 8.

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