Thorton-Pickard Anastigmat

[gimp]

This lens has been kicking around in my photo stuff for many years and I decided to give a try to see how it performs. I hacked together a bellows, a M42 extension tube and a plumbing fitting to be able to mount it to my Pentax K110D. The lens is labeled Thorton-Pickard Ruby Anastigmat. The focal length is 6 inches and max. aperture is f6.8. It has a 12 bladed diaphram and is a bit stiff to adjust. Tests show that it is soft at max. aperture. It needs to be stopped down to about f16 to achieve much sharpness. This seems to be the "sweet spot". There is no shutter. Thorton-Pickard made roller blind shutters many moons ago so it may have come off of a view camera from that era. I am attaching a few photos to show how it looks and a few to show the results of the tests. I did not have any good subjects available so please forgive the unexciting photos. Does anyone have any further info about this lens? Thanks for your interest.

[luisalegria]

Bought-in and relabelled I think.
My guess is a triplet or a rapid Rectilinear.
From the design I'm guessing some sort of triplet.

[Scheimpflug]

The Vade Mecum lists the 6in/f6.8 Ruby Anastigmat as starting in 1910, and says (in a more general sense) that while Thorton-Pickard was in business until about 1940, the lenses really centered around the 1890-1930 time frame.

Here is the optical diagram:



For what it is worth, for one of Thorton-Pickard's other lenses (the Rapid Rectilinear), the VM mentions that "Ruby" was the higher tier name, and "Amber" was the lower tier.