Carl Meyer or Karl Mayer?

It's just contract optical work. I don't know if B&J had their own optical shop or designers, or contracted some or all of that out; the answers might be in old posts; but many sellers did something like that. (For example, many of the lenses branded "Calumet" made by Ilex, Schneider, or Rodenstock have excellent reputations.) The exception may be that there are some lenses marked Dagor that B&J assembled from old stock that have a mediocre reputation, but I've never actually seen one of those.

You can count reflections of a flashlight in the lens elements, with the shutter closed so you count the front cell and rear cell separately. By moving the light source back and forth and watching which way the reflections move, you can often figure out whether they are coming off convex or concave surfaces.

Looking through the clipped corners of a ground glass to see whether you can see the lens helps measure the circle of illumination, but the circle of good definition can be smaller. For example, many lenses of Tessar design (very common) will illuminate a large radius but the definition becomes very poor in the outer parts. (IIRC, Richard Knoppow said the design had a radius beyond which it became very astigmatic; this is often called "swirly bokeh" because images become tangentially elongated.)

Anyway, there isn't a great substitute for testing the lens as you might intend to use it. For 8x10, paper negatives would probably be fine - maybe try focusing the camera on some scene with a lot of detail, adding an inch or two of front rise, taking the picture, and examining the bottom corners of the negative (top of the scene). Obviously, you have to have detail in the scene - if it's blank sky then there won't be any information. On the other hand, if you typically have blank sky in the top corners, then maybe you can get away with pushing the image circle anyway.

With the Way Keith Canham designed the wood/metal field camera, I can shift the rear standard completely off of the camera in either direction. So I have plenty of latitude to use up coverage.
It's a crappy, windy day here, so testing may be delayed.

Instead of a forgery I wonder if someone had the lens mounted in a shutter and they discarded the old barrel and thus the old name ring wouldn't fit, so they simply made a new one and misspelled it or didn't take much care. The labelling may have only been for there own use after all (in there mind).

I have one of the B&J "Carl Mayer" 12" Anastigmat lenses but in f/4.5. It's an impressively poor lens.

MTGseattle said:

With the Way Keith Canham designed the wood/metal field camera, I can shift the rear standard completely off of the camera in either direction. So I have plenty of latitude to use up coverage.
It's a crappy, windy day here, so testing may be delayed.

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Test it both at infinity and something closer up. If it's a Dagor type it would have nice soft backgrounds, especially at apertures larger than 11. I think the optimal aperture would be 16-22.

qqphot said:

I have one of the B&J "Carl Mayer" 12" Anastigmat lenses but in f/4.5. It's an impressively poor lens.

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"Impressively poor." Ha ha. That's really saying something.

Carl is thought to be the latinised spelling of the "originally Germanic variant of the male given name Charles, meaning "free man"."

Before written German was first standardised in 1901, there was a lot of variation in the spelling of names (and everything else). In medieval times, the city of Cologne, for instance, was spelled Kolne, Colne, Kollen, Collen, Coellne or Coellen before rendering the name as Coellen established itself as the official spelling in the modern era, eventually becoming Cöln and finally the modern Köln. This is just one of many examples of the letters C and K being used interchangeably, since they both represented the phoneme [k]. Standardisation was, of course, also somewhat random, c.f. Kommerz but Cannabis. The names of people, places and public or private entities sometimes retain the old-fashioned spelling with C either as part of their names (Commerzbank) or even legal forms (Sal. Oppenheim jr. & Cie).

As a first name, after having been largely abandoned in the 1980s, Carl or Karl is making a comeback. Since 2010, 18,700 Karls have been born in Germany, as well as 9,500 Carls.

I remember large lists of lenses from the Burke and James Lens Bank. It was my understanding that they acquired a ton of surplus (or spoils of war) lenses from Europe and would often coat them and sell them as new (which they were). I got some interesting lenses back then. Early 1970’s.

I need to do some more "official" testing. aside from photographing actual test targets in a controlled environment, what do people generally hold as a good test subject for a lens? City scape in varied lighting? It's cloudy and a bit gusty here this weekend. I think portraiture is way too subjective.

On an overcast day, I think all I could really get is a good idea of coverage and resolution. I would need some sun to start testing for flare and other light related artifacts I think.

I did expose some paper negatives from my back patio. I guess I should develop those. My backlog of things to develop and process is getting a bit silly (and I sit here at the computer).

For fun, my buddy and I once printed out a few copies of the USAF test chart, tape to center, middle and edge of a wide wall, and test lenses with camera on a tripod. Or you can use a brick wall.