Dallmeyer 3A

[lenser]

A Quick question. I am trying to establish a date for my Dallmeyer 3A The serial number is 66585. The patent date in June 11, 1867. The only chart I can find doesn't list out to five characters. Can anyone help please?

Thanks in advance.

Tim

[Steven Tribe]

According to the Lens Vade Mecum, Dallmeyer section (which is very extensive), this will be around 1904/5.
The patent date is when they reversed the rear pair of the original Petzval design, which made possible the soft focus facility.
The detailed sales register for Dallmeyer productions, which still exists and gives exact dates and often to whom the lens was sold (retail), doesn't continue into the 20th I believe. There is an additional patent date on many later Dallmeyers. The 3A used to be about the same price as the 6D and cost more than the 3B!
There was a close relationship between the lens diameter and the price!